XM25 "good enough"

[120mm]

http://www.military.com/news/article/army-to-test-air-burst-weapon-for-joes.html?ESRC=army.nl

In a shocking reversal, the OICW crowd simplified the XM25 and are going to release it in the "good enough" stage.

These are the same folks who sat on 120mm beehive round for 20 years because the fusing wasn't "quite" perfect. (Perfect? In a beehive round? Are you kidding me?)

Who was it that said "The perfect is the enemy of the good"?

[Ken White]

curve got hold of PEO Soldier and told 'em to shape up and get with the program. If so, it was a long overdue grab by the stacking swivel IMO.

That's just one of several reverses from them in the last couple of weeks...

[sullygoarmy]

Looks like it could fill a nice nitch, especially in an urban environment.

[reed11b]

If they further this so that the warhead technology is useable by the M109 payload rifle, I will be very happy.
Reed

[SethB]

How useful would this be? The internet is full of speculation, and I've seen a lot of guys complain that they don't want it.

But then, I don't see how different it could be from a 40MM like the MGL that the Marines are using. Actually, it probably is more effective, since the 40MM is half fuse and expends something 80% of what energy it has on the ground.

[William F. Owen]

Infantry weapons to date have permitted fighters to shoot at or through an obstacle concealing enemy threats, but the Army for years has been trying to come up with a weapon to engage targets behind barriers without resorting to mortars, rockets or grenades -- all of which risk collateral damage

So the XM-25 is to address that specific application? This is problematic to put it mildly. One per fireteam?

[sullygoarmy]

So the XM-25 is to address that specific application? This is problematic to put it mildly. One per fireteam?

That's what I was thinking, one per fire team. Still a lot more information to gather but its application within an Urban or rugged environment sounds very valid to me. The ability to put precision fires just around or over a barrier to kill a hostile without having to a) level the wall (which Mk19s are great for) b) blindly fire indirect in a restricted environement or c) use a 40mm with a larger bursting radius and far less accuracy.

This thing, however, needs to be soldier proof and have the training ammunition available for the owners to become proficient in its employment during the train up.

[The Cuyahoga Kid]

That's what I was thinking, one per fire team. Still a lot more information to gather but its application within an Urban or rugged environment sounds very valid to me. The ability to put precision fires just around or over a barrier to kill a hostile without having to a) level the wall (which Mk19s are great for) b) blindly fire indirect in a restricted environement or c) use a 40mm with a larger bursting radius and far less accuracy.

This thing, however, needs to be soldier proof and have the training ammunition available for the owners to become proficient in its employment during the train up.

Just wondering with what you were describing above, would the XM25 be an fireteam member's primary weapon or would it be a secondary speciality weapon?

[reed11b]

So the XM-25 is to address that specific application? This is problematic to put it mildly. One per fireteam?
700m and the high probability of 25mm round varients (AP?), I think that it could answere some of the HE projection hole left by the 203, even if that is not it's stated mission.
Reed

[Coldstreamer]

who made points like this...but are there not significant Positive ID issues with an munition like this? If you can't see behind the defilade, you can't tell if there are women, children, hostages or wounded littering the trench/ditch/behind the wall/in the room etc. Which leaves you open to legal questions of due diligence.

Back in the day I would have thought this was awesome. For fighting the Soviet, the North Korean or general conventional war, it is. But I don't think this is a COIN weapon system - especially in urban areas. In campaign terms (and this was a very bitter pill for me to swallow), you're better of bringing in smoke and extracting yourself than you are dropping JDAMs if you can't guarantee you won't kill a family or a wedding party. Because the vital ground remains legitimacy - upon which we will win or lose. The only exception is when you simple can't extract because the Dushka's have you in a crossfire. But again, smoke, or precision fires onto PID firing points. The Local Nationals don't give a toss if you accidentally killed their retarded nephew. You killed him. And now there's a blood feud. Better to lose the odd battle and win the war...as the American Revolution taught us.

Stick to double taps to the head with a decent round. The only interesting rifles are accurate ones.

[Ken White]

Stick to double taps to the head with a decent round. The only interesting rifles are accurate ones.We tend to forget that all too often in the rush to find an easier way...

Grenades -- 25mm, 30mm, 40mm, hand tossed or launched -- are indiscriminate weapons and often make more noise than they do actual damage. As you point out they often also do damage you'd be better off without. Time and a place for them, to be sure -- but those are rather limited. They are really defensive weapons with no place in the offense and of very little benefit in COIN, IW or UW operations.

[Schmedlap]

I share the concerns of Ken and Coldstreamer, but have a slightly different take. I think that we used 25mm and 40mm extremely effectively and could use something like the XM25 effectively, as well (though I see no pressing need for it and we could certainly make do without it).

In OIF III, my unit fought against a hodge-podge of various insurgent/terrorist factions that came and went in our AO. Lacking intelligence to do much more than fight them when they exposed themselves, that was about all that we did. In all of the firefights that we had over a year-long deployment (more than I can count), we had zero KIAs and all wounds were RTD. Nonetheless, the people in the city would complain that we "weren't fighting back." As they saw it, a few insurgents would dump multiple magazines of 7.62 at us, throw a few grenades, fire a few RPGs - all indiscriminately - and we would only return well-aimed fire. To the Iraqi citiizens, this looked like we were weak, because we were not firing nearly as many rounds, we were being cautious, and anything that got blown up was a result of enemy munitions. Even though we were killing the attackers and suffering no losses in the process and no collateral damage or civilian casualties, we somehow looked weak in the eyes of the folks in the neighborhood (didn't make sense then and still makes no sense). Explaining to them our rationale (avoiding civilian casualties) only earned us eye-rolls and disgust.

So here is how we fixed that perception problem. We started making copious use of 40mm. 40mm was actually far preferable to 7.62mm because it did not ricochet (in prior months, we accidentally hit some civilians with ricochets). On occasions when an OP spotted an IED emplacer and could have shot him with one round to the chest, we fired 40mm. We set up a free fire zone in which we told no civilians to travel. When we got attacked from that location, we peppered the place with so much 40mm, 25mm, and even hellfires, that rumors began to spread that we had surrounded and killed Zarquawi (when, in fact, we were simply making quick work of a few random combatants). In the first month of this new tact, we fired more AT-4s than in the prior six months combined. It actually caught the attention of the BDE S-4 who noticed an enormous amount of class V being pushed our way - he feared that we were stockpiling it or carelessly discarding ammo once it got dirty.

The result of these actions? We experienced no greater tactical success against the jerk-offs whom we were fighting against, but the populace had a far more favorable opinion of our efforts. Now, instead of more gunfire coming from the enemy, they saw more coming from us. It was reassuring to them and they actually thanked us for "finally" fighting back.

Now, this more liberal application of high explosives could have backfired, for the reasons cited by Ken and Coldstreamer. Had we used poor judgment as to when to fire 40mm instead of 5.56mm, or if the guys squeezing the trigger were poorly trained and misplaced their rounds, then our results would have been significantly worse. So the issue isn't the weapon system's risk for collateral damage. The issue is how well the guys who use it are trained. If they know their profession, then figuring out how to leverage the capability of yet another weapon should be no problem. A well-trained Soldier who understands the capability of a new weapon system will have no problem thinking through the repercussions of firing through a wall when he is uncertain what is behind it and his leaders should have no problem balancing the risks of doing that. So, long post short, I am not concerned about the issues cited with using the weapon. I am concerned with whether our Soldiers are properly trained and know the capabilities of the weapon. If they are properly trained, then they will not be misusing this weapon and causing collateral damage.

[ODB]

but I'll lay it out here. Many dicussions throughout the SWJ revolve around weapons. Everyone talks about the ideal round, ideal lethality, ideal caliber, firing rates, etc..... Finally someone brought up one of my biggest pet peeves (Thanks Coldstreamer). POSITIVE ID. At what distance with the naked eye can a soldier positively ID (PID) his threat in any environment? Yes, the environment makes a difference and I know all the associated factors. For arguements sake let's say open desert:

1. In local attire carrying an AK or RPG?

2. In local attire hiding an AK or RPG under his clothes?

3. In military uniform carrying an AK or RPG?

4. In military uniform with no weapon visable?

Aditionally lets use the same constraints with common current optics found within our force.

1. ACOG 4x power

2. M68 or EOTECH 0x power

3. Binos (showing my age by allowing the old M22) 7x50

4. Thermals (lightweight)

5. ELCAN M145 3.4x power

Staying in the daylight only realm, night becomes a completely different story.

I'm not talking capabilities with sniper teams and other specialties. Most discussions center around the "force" in general.

Additionally this changes based on the fight your in. Yes one can PID someone shooting from a much further distance or can they?

Based on being able to PID your target then what becomes the ideal weapon systems?

As far as anything 25mm, 40 mm or whatever the hell the next great idea fairy dreams up, maybe they should look at an effective way to train Soldiers on the weapon system. M203/M79 (yes they are still around) is the most underutilized weapon in the inventory. No one gets ammo to train with it and since this has been the case for too many years no one knows how to use it. I love seeing the deer in the headlight look when I ask why they do not have "hold off" markings taped onto their sling. Before we keep throwing new weapons, ammo, technology at the "force", we need to be able to ensure it can be effectively trained and therefore utilized to it's full capability.

[Ken White]

Both y'all have good points -- and I'll add that the 40mm is really great for bringing a car that tries to speed through a checkpoint to a screeching halt if you drop one about 15m ahead of him or her. :eek: :D

And nothing beats a .50 cal for deterring people inside buildings in most of the world.

Hadn't considered the noise angle with Arabs but I can definitely visualize it -- and the eye rolls at us being nice. :D

While all the HE grenades are essentially defensive weapons, the launchers do have uses in the offense and they need to be available because one never knows when an offensive move will get turned into a hasty or temporary defense; same reason we carry frags in the attack and Offensive Grenades are rare beasts.

Same old stuff, though -- Training and METT-TC. Always gets back to those two...

[Firn]

Some very interesting posts. I like the way the counterintuitive but yet logical consequence of a controlled demostration of loud and messy firepower can help to fulfill the objectives.

Any news about the performance of the XM25?


Firn

[jcustis]

I love seeing the deer in the headlight look when I ask why they do not have "hold off" markings taped onto their sling.

I've never heard of that technique either. What does it involve?

[jmm99]

so ODB or Ken can shell both of us - windage and elevation clicks + ?

from a target shooter only. According to a Marine friend (Vnam vintage), you also get into the target's speed and angular attitude with respect to the shooter (1/2 body width, full body width, etc., leads).

Regards

Mike

[Ken White]

From the book:

f. Marked-Sling Method. To use this method, the grenadier must--

(1) Loosen the sling, assume a kneeling position, and place the forward foot in the sling.

(2) Ensure the sling is taut and vertical between the front sling swivel and the boot. If not, the rounds will impact at a greater range than desired. To check this, tie one end of a string or thread to a weight, such as a cartridge case, and tie the other to the sling swivel. Let it hang freely, and align the edge of the sling with it to ensure the sling is vertical.

(3) Fire several rounds to determine the desired range.

(4) Where the sling is held to the ground by the foot, mark the sling with colored tape, paint, ink, or whatever is available. Mark the position of the buckles so that, if either is moved, the grenadier can return them to their original positions and be assured of constant range accuracy.

(5) If the sling gets wet, it may stretch or shrink, indirectly causing the rounds to impact closer or farther than desired.

LINK. (http://www.globalsecurity.org/military/library/policy/army/fm/23-31/f2331_6.htm)

[Uboat509]

Actually, hold offs refers to the point of aim for that weapon at a given distance. The idea is to know what your point of aim is so that you don't have to adjust the sites.

SFC W

[Ken White]

and I read what ODB said, hold offs. However, the tape and the reference just prior to the M79/M203 to me implied he was talking the sling marking with respect to shooting grenades and said 'hold offs' instead of 'expedient elevation markers for specific ranges' (handy for FPF and several other things, not least a channeling barrage from two or three launchers...).

Proper hold offs, as those you mention, IMO need to be known and remembered -- carried in the mind, not (written?) on tape on the sling. I'd ask what good they are there, particularly at night or in low vis or when one is in a terrible big hurry -- or else... :D

Or are we all missing something?

Only ODB knows and he must be out and about, having fun somewhere... :wry:

You really want to get a deer in the headlights look, ask even experienced people about fire tunnels. :D

[jcustis]

Well Ken, even though the FM doesn't provide a visual reference, I was imagining that the grenadier, with prpoer hold-offs marked on his sling, could loosen it to X length, take a knee and with the weak leg's foot, step on the tape mark, elevate the barrel until the sling was 90 deg to the ground, mounted the buttstock to his shoulder, and fired the round.

I can see how that would best work for night firing only. Or am I getting it all clearly wrong with that imagery?

[Firn]

From the book:

f. Marked-Sling Method. To use this method, the grenadier must--

(1) Loosen the sling, assume a kneeling position, and place the forward foot in the sling.

(2) Ensure the sling is taut and vertical between the front sling swivel and the boot. If not, the rounds will impact at a greater range than desired. To check this, tie one end of a string or thread to a weight, such as a cartridge case, and tie the other to the sling swivel. Let it hang freely, and align the edge of the sling with it to ensure the sling is vertical.

(3) Fire several rounds to determine the desired range.

(4) Where the sling is held to the ground by the foot, mark the sling with colored tape, paint, ink, or whatever is available. Mark the position of the buckles so that, if either is moved, the grenadier can return them to their original positions and be assured of constant range accuracy.

(5) If the sling gets wet, it may stretch or shrink, indirectly causing the rounds to impact closer or farther than desired.

LINK. (http://www.globalsecurity.org/military/library/policy/army/fm/23-31/f2331_6.htm)

Shouldn't it mean shorter range, or do I get this wrong?

Firn

[Firn]

Edit: Unless you are talking about really high angles, something like ++/+55°. With such high angles some markers on the sling would make sense and the 40mm GL would be used like a very light mortar.

Firn

[Kiwigrunt]

I've not heard (or thought) of using a 40 mm in this manner but many commando mortars are indeed 'slung' like this 60 mm Hurtsomebugger.

[Firn]

I've not heard (or thought) of using a 40 mm in this manner but many commando mortars are indeed 'slung' like this 60 mm Hurtsomebugger.

Yes that is what I thought too. The difference is that you rest the GL on your shoulder. With high arcing fire the description makes perfect sense. With a couple of markers you could also use the GL for deliberate, almost vertically plunging grenade fire on relative near enemy positions. I don't think you can use the original sights for that kind of work.


Firn

[jcustis]

Yes, that's it! The buttstock of the M16 would be placed on the ground then I suppose, even though firing it that way could be very hazardous if one wasn't fully switched on doing so.

Since we have barely enough ammo allocated to shoulder-mounted practice, I can't imagine this technique ever being taught, which is a true shame then. It would be truly badass to see that technique employed.

[William F. Owen]

Yes that is what I thought too. The difference is that you rest the GL on your shoulder. With high arcing fire the description makes perfect sense. With a couple of markers you could also use the GL for deliberate, almost vertically plunging grenade fire on relative near enemy positions. I don't think you can use the original sights for that kind of work.


The UK had a 2-inch and 51mm mortar in the platoon for 70 years. Some great genius got rid of it, and they have now brought it back as 60mm C6-210!

[Cavguy]

This discussion made me think of this: :D

http://verydemotivational.com/wp-content/uploads/2009/11/129030747535674267.jpg

[Firn]

The UK had a 2-inch and 51mm mortar in the platoon for 70 years. Some great genius got rid of it, and they have now brought it back as 60mm C6-210!

I agree that this would be a rather interesting technique especially with the low-velocity 40x46 grenade. You could cover a range of 50 to 400m with with the classic low-arc indirect fire and plunging one. This could bridge some gaps left by the heavier and more efficient mortar fire support from further away.

As jcustis said there won't be much training time for this specific technique. But which GL would be suitable for this type of support?

a) A rifle with an underslung GL (M203, M320)

b) A stand alone GL (M320)

c) A multiple GL (M32) - could be interesting due to the bursts of grenades.

d) A GMG (grenade machine gun) - depends on the tripod. If MGs were used for long range indirect fire why shouldn't GMGs not be used for long range plunging "mortar" fire?


What about the M320. It has side-mounted sights and even a LRF. There should be a way to turn the sight around 90°. In this case it should be easier to get the rounds on target. Or we use the good old slinging technique with alot of marks after having first lazed the target. Then give the GL a talented guy and let him shoot a lot of rounds. Then make him the squads/platoons first grenadier or light mortarier. He could operate from behind a wall with another guy reloading and an observer close by directing his fire. Does almost sound like a 51mm mortar :)

Heavy things like the M32 might be a good crew served weapon for a platoon mountain of infantry. But you can carry alot more rounds (12-15?) by bringing instead an M320 with you. If you have your vehicles nearby the situation changes quite a bit.

I do think that a true mortar is a more efficient solution. But why shouldn't we make better use of weapon which has become practically a standard staple for every infantry squad across NATO? We just have to carry a marked sling, an opern mind and more training in you head to do just that.


Firn

[Kiwigrunt]

I think there could be some advantages to this technique with 40 mm, especially for lobbing some grenades over a high obstacle like a wall. I can see some negatives though, some of which have been mentioned:

• Requires lots of practice rounds. Good luck with that. There are typically 6 to 9 grenadiers to a platoon against only 1 (for armies that have’m) commando mortar. They would all need to be trained in this additional technique. They don't get enough playtime with 40 mm as it is.
• A 60 mm bomb makes a reasonably big bang and can therefore afford to be off target a bit and still be effective. A 40 mm grenade needs to be pretty much bang on (pun intended) or all it does is throw up a bit of dust. So lobbing 40 mm in an indirect fire mode may be somewhat disappointing in most cases.
• The ‘aim by sling’ method is not particularly scientific and accuracy will be easily affected, even just by not being on perfectly level ground (between baseplate/buttstock and locking foot). This will exacerbate the above point. Firn’s suggestion of using a better sight would make more sense.

So it would a useful technique to add to the toolbox but I think we need to be careful with assuming that we can easily and effectively use a light direct fire weapon in the indirect fire role. Armies that do not yet have them are IMO better off with adding a 60 mm commando mortar at platoon level ….. sure, more weight, but the tool has been specifically designed for this role.

While we’re drifting towards commando mortars, the South Africans use two different conversion sets for their M1 mortar. One uses the ‘aim by sling’ method. The other uses a clip-on handgrip with an incorporated laying table/levelling bubble thingy. Now a simplified version of that could work on a 40 mm. That would however add yet another sticky-out thing to the weapon, to add to the Christmas tree effect.

[Fuchs]

About OICW / XM29 / XM25:

http://www.youtube.com/watch?v=AtGpWnLi45U

The ROK has its own.

[jcustis]

Now a simplified version of that could work on a 40 mm. That would however add yet another sticky-out thing to the weapon, to add to the Christmas tree effect.

You know, it need not...all it would take is a graduated level that could attach to the side of the mil-std 1913 Picatinny rail. Our current M224 60mm has that built into the firing assembly. It just needs to be small, lit by a tritium ampule, and could clip on via any number of attachment means that are already in use for side-mounted sling swivels.

A couple rounds to get the thing zeroed and locked down with Loctite, and there you have it. No need to fiddle with a sling marking system that would rely on the grenadier to pause and adjust it to the appropriate length for use. There would be slight variation due to the surface the buttstock rests on (sand, gravel, boot tip, etc.). The only thing limiting this setup would be the degree of accuracy required in the requirement document, as it related to mounting the sight to the rail, adjusting the rail in relation to the launcher receiver, etc.

We might never get there due to tight tolerances required by whomever would generate the specifications, but my light bulb just clicked on. :D

[Schmedlap]

We had IR aiming lights for our M203's as early as OIF III. A few of our enlisted Soldiers who were RFS'd from the Rangers said that they had them a couple years before that. So long as you estimate range within the ballpark (which you need to do anyway if using leaf or quadrant), it's very accurate. Even in training, guys who had never fired a 203 before (really, we had a bunch of people who had never fired one - unbelievable) they were scoring first-round hits on targets at 250 meters at night. It was kind of bulky, but lightweight. I think the latest generation are far less bulky and even lighter.

See the bottom of the page here: https://peosoldier.army.mil/FactSheets/PMSW/SW_IW_M203DNS.pdf

[William F. Owen]

I agree that this would be a rather interesting technique especially with the low-velocity 40x46 grenade. You could cover a range of 50 to 400m with with the classic low-arc indirect fire and plunging one. This could bridge some gaps left by the heavier and more efficient mortar fire support from further away.


No need. 40mmx46 medium velocity has been with us for 4 years now. Shoots to 800m, with 30% more blast, from an M-203 or M79 type. The reason it's not in service is purely one of bureaucracy, as far as I can tell. It's certainly no secret and the infantry fire support topic for some time.

Light Mortars are excellent. Not as inaccurate as commonly supposed, very fast into action, and very high rate of fire. Because they don't "fire blanks" on exercise, everyone underestimates their importance. All you need for sights is an "Inclinometer" and something to align the weapon with. There are even computer training packages for them.

I used to carry the 51mm as a Platoon Sergeant.

[Firn]

An interesting debate.

I envisioned not a true light mortar but a GL which could be used to aid the squad/element to fulfill their task. IMHO a true organic mortar support should always be available, best if coming from a location which can be easily supplied with ammunition and as heavy as sensible. Commando and light mortars are certainly excellent tools if more efficient mortar support can not be delivered. Kiwigrunt's points are pretty much spot on.

I also considered the low velocity of the classic 40mm grenade fitting because it would be ideal for short to medium plunging fire. But all things considered the medium velocity one seems to be the far better choice. A good inclinometer would be of course an ideal and even cheap and rather light solution. I do not know if the modern sights on the new GLs coming out are able to cover the whole reach of the faster grenades - so the inclinometer could also be valuable for the longer ranges. The IR lights Schmedlap mentioned could have one included.

To come back to the original topic. Part of the promise of the XM25 is that you can engage an enemy in a room or behind a wall thanks to ranged airbursting. Perhaps we will see the XM25 grenade's airbursting modes also in the 40mm grenades. But thanks to modern sights and aiming systems the not so fancy 40mm can already be very accurate.

To use this great accuracy and the great versatility offered by the large variety of rounds one needs also an experienced hand and a good supply of ammuntion. So sometimes one might have to sacrifice some other weight/firepower to carry more rounds for this weapon.


Firn

[Schmedlap]

I guess I just don't understand what need is being fulfilled by the XM25.

It would be neat to be able to hit a guy hiding behind a berm with an airburst. I can think of zero occasions when I needed to do this. Anyone else? Even if there were a handful of cases, is this narrow range of uses worth the extra weight, bulk, new lines of ammo and parts, and the re-training that would be necessary?

There were a few occasions when there was someone in a building who needed to be killed before the building could be assaulted. That's why we train to put 40mm through windows. It's surprisingly easy.

[jcustis]

It would be neat to be able to hit a guy hiding behind a berm with an airburst. I can think of zero occasions when I needed to do this. Anyone else?

I can think of several times in Iraq where that would have been appropriate. In Afghanistan (headed there next), isn't that what wall-fighting is all about?

[Firn]

I guess that only the battlefield can decide if the system XM25 is worth it. Perhaps it would be helpful to test it as a support weapon for the platoon and not as an substitution of one UGL at the squad level. I gave it a quick glance the target acquisition/fire control system coupled with 4x Thermals sounds quite impressive. If only that works it would be a nice addition to any platoon :D

Wikipedia gives it a rundown:

Target acquisition/fire control (XM104).

* Weight: 2.54 lbs
* 4x thermal sight with zoom.
* 2x direct view optical sight.
* Ballistic computer.
* Digital compass.
* Laser rangefinder.
* Ammunition fuze setter.
* Environmental sensors.

So you could use it to generate good target solutions for the other weapon systems (mortar, sharpshooter, artillery, GL...)

Other than that it might be used also as rifled shotgun on steroids. If the gun itself works one could give the gunner always some slugs. ;)


Firn

[Firn]

I gave the XM-25 now a closer look from my armchair. The decision to drop the rifle part seems to be very sensible. You have a far less heavy and cumbersome weapon without another 2kg + hanging under the center and front of the grenade launcher. It focuses the scope of the weapon on supporting the riflemen and does away with the rather naive vision that every grunt will have one.

The design and the choice of the caliber should allow the grenadier to use it as his sole long weapon - looking at it also as a bulky 5-gauge rifled shotgun with a huge sight. A light pistol as a sidearm might still be a wise choice, at least until one can be certain of its mettle. This GL will fire slugs just fine and perhaps one could make buckshot work in it. Rifled barrels spread buck much more than smooth ones, at 10m they will be all over a torso. To reduce the weight of the self defense ammuniton sabots could be used instead of full-size slugs. It should be easy to design a breeching round for it.

So it covers quite some needs. It might also intimidating than a M-4, and can make a visible and messy statement in the same way Schmedlap's guys used the 40mm. It should do it's work from closer (arming) and longer distances than the M203. The long barrel ought to give not only good range, but also a more moderate muzzle report. Relative quick semi-automatic shooting should be possible due to the lighter recoil and the rather heavy weapon.

Just some quick rambeling...


Firn

[Fuchs]

It focuses the scope of the weapon on supporting the riflemen and does away with the rather naive vision that every grunt will have one.

One per fire team was the official plan for the OICW.

[Firn]

One per fire team was the official plan for the OICW.

Really? I guess I crossread it with the new Korean rifle. Anyway this makes of course much more sense.

Another thoughts.

A 25x40mm grenade should weight only around a third of a 40x46mm or something like 80 g instead of 230 g. Thus you can carry a lot of them, especially if the Grenadier can do away with another long weapon and maybe even the pistol thanks to some "defensive" rounds (slugs, buckshot, AP).


Firn

[Kiwigrunt]

A 25x40mm grenade should weight only around a third of a 40x46mm or something like 80 g instead of 230 g.

So how effective can such a small grenade really be, assuming it will air-burst a few metres away from the target? I assume an advantage of this air-burst over the 40 mm is that no energy is lost in the ground. Or, come to think of it, into the back wall of a room after firing it through a window.

Also from Firn:

So it covers quite some needs.

I'm not sure that all the examples you gave can really be seen as needs. Some seem more of a justification to help warrant it's existence. For instance, a buckshot or flechette round seems to me a heavy, bulky and expensive alternative to 5.56 or 7.62. A breaching round however could have merrit.

[Firn]

S
I'm not sure that all the examples you gave can really be seen as needs. Some seem more of a justification to help warrant it's existence. For instance, a buckshot or flechette round seems to me a heavy, bulky and expensive alternative to 5.56 or 7.62. A breaching round however could have merrit.

We will have to wait and see if the XM25 can fulfill it's core and much advertised function, taking out people behind cover through a precisely placed air-bursting round.


Let us talk about the possible functions and the needed ammuntion:

a) Rapdily eliminating or suppressing enemy targets on open ground and in defilade from short to long distances with a low risk of collatoral damage and relative lightweight rounds. The small burst radius should allow a short (10m?) arming range-> HEAB

b) Defeating or stopping lightly armored targets, such as vehicles or personnel behind cover at short to long ranges.-> AP (HEAT?), HEAB

c) Killing enemies at close range, for example while clearing a house or a trench Essentially selfdefense, this task is better left to other soldiers. -> Sabot Slug ( good range, good, safe penetration power), Buckshot/Flechette ( very short range, medium penetration), not armed HEAB

d) Breeching doors. -> Breeching round

e) Crowd/Riot control. Less-than-Lethal rounds -> bean bags, soft slugs. I'm generally sceptical about their use, but it should be possible to create some sensbile ones to give trained hands an important toolset.

f) Training. -> Training round


All in all the 25mm grenades won't replace the 40mm, as it will still be for many uses (smoke, illumination, WP, disposable camera, sheer bang) the better choice.


Firn

P.S: It seems that the XM25 with solid rounds is somewhat between downloaded 6- and 8-bores (http://www.riflemagazine.com/magazine/article.cfm?magid=44&tocid=553) favorite big game rifles of the 19th century. A thinner sabot will result in less weight and more muzzle velocity.

[Tukhachevskii]

Let us talk about the possible functions and the needed ammuntion:

a) Rapdily eliminating or suppressing enemy targets on open ground and in defilade from short to long distances with a low risk of collatoral damage and relative lightweight rounds. The small burst radius should allow a short (10m?) arming range-> HEAB

b) Defeating or stopping lightly armored targets, such as vehicles or personnel behind cover at short to long ranges.-> AP (HEAT?), HEAB

c) Killing enemies at close range, for example while clearing a house or a trench Essentially selfdefense, this task is better left to other soldiers. -> Sabot Slug ( good range, good, safe penetration power), Buckshot/Flechette ( very short range, medium penetration), not armed HEAB

d) Breeching doors. -> Breeching round

e) Crowd/Riot control. Less-than-Lethal rounds -> bean bags, soft slugs. I'm generally sceptical about their use, but it should be possible to create some sensbile ones to give trained hands an important toolset.

f) Training. -> Training round



g) Coudln't the XM25 provide a very useful small unit (plt level) air-defence weapon against small tactical UAVs (not the UCAV though) with its flachette rounds?:cool:


The Swedes have been busy too; The Swedish Squad Support Weapon Programme (http://www.dtic.mil/ndia/2004arms/session3/arvidsson.pdf)

[Tukhachevskii]

g) Coudln't the XM25 provide a very useful small unit (plt level) air-defence weapon against small tactical UAVs (not the UCAV though) with its flachette rounds?:cool:


The Swedes have been busy too; The Swedish Squad Support Weapon Programme (http://www.dtic.mil/ndia/2004arms/session3/arvidsson.pdf)




p.s. if link doesn't work search for SSW Presentation at ESAS 2003 on google or a search engine of your choice:D

[Kiwigrunt]

It's (http://soldiersystems.net/2010/10/14/breaking-news-army-deploying-xm25-to-afghanistan/) coming.

[DMR]

12 pounds?

Ok let's ask a few questions:
1. What are the dimensions and weight of one mag. How many can a soldier carry before they bulk out=basic load.

2. At twelve pounds plus basic load their is no way the soldier is also going to have a M-4. Pistol becomes a manditory addition. This = Army has to buy more pistols or transfer pistols from someone that has them now.

3. 1 per fireteam would seem to mean either the M-203/320 or the Rifleman have to go. That position will become the XM-25 gunner.

4. At least in the current generation it is two bulky to "tuckaway" somewhere so a soldier could at least carry an M-4 with one or two mags to defend them selves.

So we end up with a every specilized weapon that may go bing for ammo in the average fire fight very quickly and the soldier is running around (you would hope) with at least a M-9 to defend themselves.

If they add them to the current MTOE's in a Arms Room fashion, ie. I'm going to leave the M-320's at home today because we will be operating mounted, then maybe, but for the oppertunity cost I would have to say no thanks.

[TAH]

12 pounds?

Ok let's ask a few questions:
1. What are the dimensions and weight of one mag. How many can a soldier carry before they bulk out=basic load.

2. At twelve pounds plus basic load their is no way the soldier is also going to have a M-4. Pistol becomes a manditory addition. This = Army has to buy more pistols or transfer pistols from someone that has them now.

3. 1 per fireteam would seem to mean either the M-203/320 or the Rifleman have to go. That position will become the XM-25 gunner.

4. At least in the current generation it is two bulky to "tuckaway" somewhere so a soldier could at least carry an M-4 with one or two mags to defend them selves.

So we end up with a every specilized weapon that may go bing for ammo in the average fire fight very quickly and the soldier is running around (you would hope) with at least a M-9 to defend themselves.

If they add them to the current MTOE's in a Arms Room fashion, ie. I'm going to leave the M-320's at home today because we will be operating mounted, then maybe, but for the oppertunity cost I would have to say no thanks.

It also means two fewer Soliders in each rifle sqaud capable of shooting 5.56 in support of the operation. 6 fewer per Plt and 18 fewer per company. Adds up quick!

[Rifleman]

Seems like one per squad would be a better idea.

And since trying to conduct an enveloping attack with one fire team in a nine-man squad is a usually a fantasty anyway it won't matter that the fire teams aren't balanced.

Maybe a different story if the squad is reinforced but usually they're understrength.

[120mm]

Note that in the article they are calling for 36 per battalion. It should be easy enough to figure out at what level they are being deployed based on that number.

[Rifleman]

For light TOEs 36 per battalion sounds like one per rifle squad plus three unassigned in the company arms room.

One weapon like that per fire team is just too much in small Army squads. Too many suppression weapons equals not enough riflemen to clear with.

Now, if the Army squad would just get rid of one of the SAWs. One light machine gunner, one grenadier and six or seven riflemen would be better. Balanced fire teams made better sense in the days of the BAR and M1, especially in big USMC squads.

[TAH]

For light TOEs 36 per battalion sounds like one per rifle squad plus three unassigned in the company arms room.

One weapon like that per fire team is just too much. Too many suppression weapons equals not enough riflemen to clear with.

According to the May 2010 version of the Fort Knox Special Manual on BCTs,

An Infantry Bn has 15 M320 in its HHC, 20 M320s in each of three rifle companies and 16 in its Wespons Co, for a total of 91 in the Bn.

So, it is clearly NOT a 1 for 1 swap.

[Uboat509]

It looks like one per squad but I still don't see the point. According to Wikipedia the system weighs 14 pounds but it doesn't say if that is loaded or empty. I am guessing empty. It gives the weight of the Target acquisition/fire control but does not say if that weight is included or not. Logic would suggest that it is included in the weight of the system but since this data apparently comes from the company who is trying to market it to the military, logic may not apply. There is no weight given for the ammo. There has been no data that I have seen on the effective burst radius of the round. I also have questions about what will happen when the highspeed optics fail. I would like to know what secondary weapon the gunner is supposed to carry. Most importantly, I would like to know why we need this. This appears to be a very narrow niche weapon. It appears that it can only really do one thing that the M203 can't. Is it really worth the cost or could that money be better spent elsewhere?

[Firn]

You know, it need not...all it would take is a graduated level that could attach to the side of the mil-std 1913 Picatinny rail. Our current M224 60mm has that built into the firing assembly. It just needs to be small, lit by a tritium ampule, and could clip on via any number of attachment means that are already in use for side-mounted sling swivels.

A couple rounds to get the thing zeroed and locked down with Loctite, and there you have it. No need to fiddle with a sling marking system that would rely on the grenadier to pause and adjust it to the appropriate length for use. There would be slight variation due to the surface the buttstock rests on (sand, gravel, boot tip, etc.). The only thing limiting this setup would be the degree of accuracy required in the requirement document, as it related to mounting the sight to the rail, adjusting the rail in relation to the launcher receiver, etc.

We might never get there due to tight tolerances required by whomever would generate the specifications, but my light bulb just clicked on. :D

Somebody's light bulb clicked on a little earlier, and designed the (rifle ) grenade sight T59, for the use of low-angle and high-angle fire. It could be fitted to pretty much every US WWII rifle and carbine. :D

Slings were already marked with tape in WWII, usually with the aid of a clinometer. When used in the high-angle role, an additional, rimmed .45 propulsion cartridge was inserted into the launcher tube.

The interesting thing about rifle grenades was the broad range of uses, already in WWII. Here are just some of the lesser known ones:

- After removing the detonator, a 30-yard cordtex (explosive 1/4 inch cord) was tied to the (Mills) rifle grenade and shot across the minefield, clearing a long and 8-inch narrow path. By using two such paths 10 feet apart, a cordtex net could be dragged across the minefield to open a 10-feet street (Source: British Commandos, Nr.1 of the often mentioned Special Series)

- "Grapnel" Grenades were first improvised to clear from a covered position trip-wire up to a 100 yards away. A simple AT rifle grenade got almost completely stripped down and a wooden plug with three inserted hooks got fixed with a screw as new head. A heavy 150 yard chalk line was attached and coiled up. ( Combat Lessons 4, WWII series)

- In a similar way com. wire was layed across streams, to up to 130 yards. (Combat lessons 6, WWII series)

- 60mm Mortar bombs were attached by wire and pliers to the grenade projectors M7 and M1 and fire to up to a range of 110 yards. Used to clear houses and hedgerows. (Combat lessons 6, WWII series)

- WP (smoke) rifle grenades with reduced WP charge were used by grenadiers to mark hidden targets, especially for the supporting tanks. (The reduction of the WP avoided the concealment by the very smoke) (Combat lessons x, WWII series)

- Some German rifle grenades could also be thrown by hand, lightening the combat load. This was considered to be very useful for mobile, light units operating far from the next base. ( Other countries had also special rifle adaptors for hand grenades) (Small unit action in Russia)

All in all it seems that the rifle grenade can still be useful in some "odd" or special jobs which need an odd or oversized warhead shape. Breeching, Mine-clearing, Grapnelling are just some of them.

The 40mm grenades at one side of the spectrum and the shoulder-fired weapons on the other seem to cover the big rest well enough. We will see how well the 25mm grenades widen that spectrum.

[SJPONeill]

So how effective can such a small grenade really be, assuming it will air-burst a few metres away from the target?

Efficiencies in fragmentation rounds can be realised by hyping up the technology and quality control in the fragmentation shell so that it fragments reliably and consistently over the required pattern...just like the original hand grenades had a cast sheel that might even shatter into a even spread, or simply just break into a small number of large chunks...5-6 years ago, Denel reckoned that it had made the frag pattern of its new 105mm round consistent and reliable enough to offer the same spread as the 155mm rounds of the time...

[JMA]

So the XM-25 is to address that specific application? This is problematic to put it mildly. One per fireteam?

It seems it needs to be supplied with a bipod and possibly a standing aiming rest. It weighs 14lbs (6.35kg) unloaded and that means most soldiers will have a problem aiming and carrying it with sufficient ammunition. Base camp defence?

[JMA]

...but are there not significant Positive ID issues with an munition like this?

The requirement for a positive ID before firing is the best reason why the leading Western countries (US, UK) should make more use of proxies to fight their wars for them.

[B.Smitty]

http://kitup.military.com/2011/02/inside-the-xm-25-after-action-reports-from-afghanistan.html

The XM-25 has fired 55 rounds in nine firefights between Dec. 3 and January 12, when the formal Forward Operational Assessment ended. Officials say the weapon “disrupted” two insurgent attacks against an observation post, destroying one PKM machine gun position in one of those attacks. That is where the ”usually our engagements last for 15-20 minutes. With the XM-25 they’re over in a few minutes” line came from.

The XM-25 also “destroyed” four ambush sites during engagements on foot patrols or movements to contact. In one instance, the 25mm HE round exploded on a PKM gunner and he was either wounded and fled or scared and fled, but dropped his machine gun, which Soldiers later recovered.

Two units within the 101st Airborne have used the XM-25 since November. The first unit fired 28 rounds in four TICs, the second unit fired 27 rounds in five TICs.

[Firn]

Somebody's light bulb clicked on a little earlier, and designed the (rifle ) grenade sight T59, for the use of low-angle and high-angle fire. It could be fitted to pretty much every US WWII rifle and carbine. :D

Slings were already marked with tape in WWII, usually with the aid of a clinometer. When used in the high-angle role, an additional, rimmed .45 propulsion cartridge was inserted into the launcher tube.

The interesting thing about rifle grenades was the broad range of uses, already in WWII. Here are just some of the lesser known ones:

- After removing the detonator, a 30-yard cordtex (explosive 1/4 inch cord) was tied to the (Mills) rifle grenade and shot across the minefield, clearing a long and 8-inch narrow path. By using two such paths 10 feet apart, a cordtex net could be dragged across the minefield to open a 10-feet street (Source: British Commandos, Nr.1 of the often mentioned Special Series)

- "Grapnel" Grenades were first improvised to clear from a covered position trip-wire up to a 100 yards away. A simple AT rifle grenade got almost completely stripped down and a wooden plug with three inserted hooks got fixed with a screw as new head. A heavy 150 yard chalk line was attached and coiled up. ( Combat Lessons 4, WWII series)

- In a similar way com. wire was layed across streams, to up to 130 yards. (Combat lessons 6, WWII series)

- 60mm Mortar bombs were attached by wire and pliers to the grenade projectors M7 and M1 and fire to up to a range of 110 yards. Used to clear houses and hedgerows. (Combat lessons 6, WWII series)

- WP (smoke) rifle grenades with reduced WP charge were used by grenadiers to mark hidden targets, especially for the supporting tanks. (The reduction of the WP avoided the concealment by the very smoke) (Combat lessons x, WWII series)

- Some German rifle grenades could also be thrown by hand, lightening the combat load. This was considered to be very useful for mobile, light units operating far from the next base. ( Other countries had also special rifle adaptors for hand grenades) (Small unit action in Russia)

All in all it seems that the rifle grenade can still be useful in some "odd" or special jobs which need an odd or oversized warhead shape. Breeching, Mine-clearing, Grapnelling are just some of them.

The 40mm grenades at one side of the spectrum and the shoulder-fired weapons on the other seem to cover the big rest well enough. We will see how well the 25mm grenades widen that spectrum.

Der Kampf der Infanterie (http://www.youtube.com/watch?v=qmibfBVMJB8&feature=related), the fight of the infantry, a swiss army movie of 1976 is interesting for a couple of things I noticed. Of course the Swiss German makes it rather hard to understand the talking of the soldiers, even for fluent German speakers.

Rifle grenades are featured very often both while defending and attacking, against infantry and AFV.

1) An strongpoint gets attack one of the defender calls out the range, and another adjusts his bipod with engraved range scales on it. Later you see how different defenders engage out of the trench the attacking infantry with massed indirect rifle grenade fire.

2) Armored infantry advances through forests and meadows in alpine terrain and,while still mounted, get attacked by various AT-weapons, like mines, ATM and rifle grenades.

3) Airmobile infantry inserted behind the frontline get counterattacked by infantry supported by MGs, mortars. Some riflemen get tasked to support the advance by using their rifle grenades in the same mini mortar-like role as seen in 1).

The rifle grenades were quite heavy and thus the recoil was wild, making it quite (un)popular in soldier stories. In direct fire the shooter had to be careful to follow the correct procedure.

Overall the greater ease of use of the 40 mm GL as well as the spread of ATM might have been key factors in the decline in popularity of rifle grenades. With training time ever limited it certainly is sensible to focus it on weapons expected to be widly in use.

[Fuchs]

The UBGL is essentially an (almost) always ready-to-fire version of WW2-era rifle grenades that used muzzle cups (such as German Schissbecher (http://en.wikipedia.org/wiki/Schiessbecher)).

Modern rifle grenades are descendants of those WW2-era rifle grenades that used a rather stokes-like principle (sitting on the muzzle).


The UBGL and stnad-alone GL designs add (just like the Schiessbecher) a certain fixed cost of mass. No matter how many grenades you carry, you gotta carry those 1-4 pounds of weapon.

Thus we have today the choice between
* rifle grenades with zero fixed costs (mass) thanks to ladder sights on the grenade itself
OR
* grenade launchers with fixed costs (mass), which in present GL designs is somewhat outweighed by less slow use (I wouldn't say 'quick' as long as you need to flip up sights or carry a carbine in ready position but have to switch to a stand-alone GL). The variable costs (mass per shot) is also smaller.

Recoil as a problem rather favours rifle-attached solutions, for the additional weight reduces felt recoil. A given warhead mass and a given trajectory (~muzzle velocity) will yield about the same recoil all else equal (weight and thus recoil differences between fin and spin stabilisation may occur, though).


In the end, today's rifle grenades have two niches:

(1) Whole small unit grenade salvo without many heavy GLs
(2) Large calibre grenades (see the Simon doorbreacher rifle grenade)

GLs have other advantages

(1) Potential exploitation of Medium-low pressure principle.
(2) Can be carried ready for fire in UBGL
(3) Can be a multi-shot weapon (revolver or pumpgun principle usually)
(4) already standardised
(5) No need for bullet trap or special ballistite blank cartridge
(6) Can be used on weapons of different calibres without aiming issues
(7) The limitation to few soldiers inherently leads to higher practice standard by specialisation in practice
(8) Propellant power is independent of rifle/carbine calibre and barrel length.

The French, Israelis and some other countries make still much use of rifle grenades.

[Firn]

The UBGL is essentially an (almost) always ready-to-fire version of WW2-era rifle grenades that used muzzle cups (such as German Schissbecher (http://en.wikipedia.org/wiki/Schiessbecher)).

Modern rifle grenades are descendants of those WW2-era rifle grenades that used a rather stokes-like principle (sitting on the muzzle).


The UBGL and stnad-alone GL designs add (just like the Schiessbecher) a certain fixed cost of mass. No matter how many grenades you carry, you gotta carry those 1-4 pounds of weapon.

Thus we have today the choice between
* rifle grenades with zero fixed costs (mass) thanks to ladder sights on the grenade itself
OR
* grenade launchers with fixed costs (mass), which in present GL designs is somewhat outweighed by less slow use (I wouldn't say 'quick' as long as you need to flip up sights or carry a carbine in ready position but have to switch to a stand-alone GL). The variable costs (mass per shot) is also smaller.

Recoil as a problem rather favours rifle-attached solutions, for the additional weight reduces felt recoil. A given warhead mass and a given trajectory (~muzzle velocity) will yield about the same recoil all else equal (weight and thus recoil differences between fin and spin stabilisation may occur, though).


In the end, today's rifle grenades have two niches:

(1) Whole small unit grenade salvo without many heavy GLs
(2) Large calibre grenades (see the Simon doorbreacher rifle grenade)

GLs have other advantages

(1) Potential exploitation of Medium-low pressure principle.
(2) Can be carried ready for fire in UBGL
(3) Can be a multi-shot weapon (revolver or pumpgun principle usually)
(4) already standardised
(5) No need for bullet trap or special ballistite blank cartridge
(6) Can be used on weapons of different calibres without aiming issues
(7) The limitation to few soldiers inherently leads to higher practice standard by specialisation in practice
(8) Propellant power is independent of rifle/carbine calibre and barrel length.

The French, Israelis and some other countries make still much use of rifle grenades.

I mostly agree with this summary.

It is interesting that early post-WWII AT rifle grenades shared the technology, warhead or even more parts with the missiles fired by rocket launchers. This goes for the French (AC58 - WASP 58), Swiss (Gewehrgranate 58 - Raketenrohr) and the USA (M31 HEAT - LAW72).

For direct fire the max. effective ranges seem to have been around 75 to 100 m. Used like spigot-mortar with rocket-boosted grenades ranges up to 550 m, although shorter ranges would have been the norm. Velocities of up to 75 m/s were achieved, but with 7,62 mm blanks and as said with a rocket boost. Not much compared to the claimed 250 m/s of the Wasp and still a lot slower than the 145 m/s of the LAW72.

The Swiss army used the training rifle grenade 58 to lay cable across obstacles, something which was already done in WWII.

All in all I could imagine those niche uses ( points taken partly by Fuchs) with modern assault rifles.

(1) Whole small unit grenade salvos (HEDP, etc)**
(2) Large calibre niche grenades (SIMON, smoke grenades)*
(3) Cable, Grapple, Cordex projector


All of them should be bullet-trap or -through types. If practical, the lighter rifle grenades (HE/HEDP) could also double as defensive handgrenades, like some German WWII ones.

*Heavy AT grenades don't seem to make sense enough compared to light rocket launchers like the LAW72 to develop, train and carry them.

**Light mortars have taken part of that role, even if the rifle grenades are of course a different kettle of fish.

P.S: I guess Schissbecher is a typo :)

[Fuchs]

Some typos happen unconsciously, but honestly...

It was a stupid design, about as much over-engineered as the 5 cm leGrW 36 (platoon mortar). German engineers of the 30's were totally in love with spin stabilisation and neglected fin stabilisation (see also Rz 65, Nebelwerfer 41).

This, by the way, enabled the 8th air force to use its quite poor heavy bomber designs (which were mere target practice for fin-stabilised low-tech R4/M rockets!) in the first place.

[Compost]

XM25 could be “good enough” for use in some kind of adventure park but virtually useless everywhere else. See post 928 on Roles and Weapons with the Squad.

In the end, today's rifle grenades have two niches:

(1) Whole small unit grenade salvo without many heavy GLs
(2) Large calibre grenades (see the Simon doorbreacher rifle grenade).

That first niche would require prompt supply of spare rifles, carbines and attachments to replace those damaged or wrecked delivering volley fire during operations, and earlier in range practice and field exercise ?

What useful niches (other than salvo line throwing) are left when a section/squad typically has hand grenades, UGLs and demo charges plus Armbrust, M-72 or suchlike; and when a modern platoon can have a 60mm handheld mortar (issued or attached) and also one or more 40mm MGLs ?

[Compost]

It has been pointed out that lack of calibre makes for confusion. Can sentence be corrected?

[Fuchs]

GLs have other advantages

(1) Potential exploitation of Medium-low pressure principle.
(...)

I am disappointed. Why did nobody point out that rifle grenades inherently kind of exploit the high-low pressure principle?

------------------------

@Compost: Why should a salvo of rifle grenades wreck the weapons? The rifle/carbine is largely unaffected by the use of rifle grenades.

UBGLs and MGLs will typically not be together in a small unit. 40 mm medium velocity ammunition also puts a bold question mark behind a platoon ("commando", "light" or "patrol") mortar since it has ~700 m range and enough physical effect to achieve similar psychological effect.

[Compost]

Compost: Why should a salvo of rifle grenades wreck the weapons? The rifle/carbine is largely unaffected by the use of rifle grenades..

First, “bullet-trap or –through designs” produce a pressure pulse that is higher than the normal pressure for which the rifle or carbine was primarily designed. For grenade launching to be approved that higher pressure must be within safety limits. Perhaps that also means there are no cumulative affects and my residual concern there is wrong.

Second, the user expects the recoil to be higher and anyway to achieve range a recommended method of firing is with the butt grounded. If/when the weapon is held down with inadequate pressure – especially against a hard surface – the butt is liable to damage together with any frangibles attached to the weapon. That is likely to occur due to haste and stress during operations and exercise and training. An expert is unlikely to make that mistake but in volley/salvo fire only some will be rifle grenade experts.

UBGLs and MGLs will typically not be together in a small unit. 40 mm medium velocity ammunition also puts a bold question mark behind a platoon ("commando", "light" or "patrol") mortar since it has ~700 m range and enough physical effect to achieve similar psychological effect.

Agree UGLs and MGLs and mortars will typically not all be together in a small sub-unit such as a section/squad but at least two of the three are on issue to some modern platoons. The USMC platoon now has one or more MGLs and its squads have UGLs able to fire LV and MV rounds.

However, a light mortar is longer ranged than 40mm MV weapons and can launch a significantly heavier and more damaging weight of ‘munitions’ particularly including HE, line, smoke and exotics such as para-cameras and micro-UAVs. If a light mortar is needed by a USMC platoon then a 60mm can be obtained from the company weapons platoon.

Hence my phrase: “when a modern platoon can have a 60mm handheld mortar (issued or attached) and also one or more 40mm MGLs “.

In line with that concept, the Br Army platoon has regained a light mortar and its sections have UGLs. I believe that 60mm mortar would be carefully kept on issue (although not invariably carried on light infantry operations) even if the platoon were to gain one or even two of the increasingly attractive 40mm MGLs.

[Fuchs]

This is the very first time that I hear about some "pressure pulse" problem associated with rifle grenades. I have some physics skills, but I can only imagine a tiny effect after the time when the bullet reaches the muzzle. The grenade might act as a cloture (hardly with bullet-thru, though) for a very, very short moment.

I doubt that this has any measurable effect, since barrels have a decent safety margin anyway.


About the buttplate damage; again entirely new to me. Soldiers do a lot with their rifles and rifles have to be tough anyway. The recoil of a rifle - even with a heavy projectile - should be well within the limits of normal harsh treatment.

[Ken White]

The only problems with rifle grenades is that they are heavy, inaccurate and tie up the rifle from which they're fired. Due to those shortfalls, they are disappearing from inventories and rightly so. A 40mm under a rifle is a far better solution.

Whether the XM-25 is going to be a plus for combat -- heavy combat -- remains to be seen. For combat operations like the current efforts, it does what it's supposed to do -- which is more than can say for most of the tripod or vehicle mounted AGLs. Those things are significantly overrated. Though they are fun to play with... :D

Last I heard, Canada proposed to replace their 60mm mortars with 40 AGLs. I hope, for their sake, that's not true... :o

[Kiwigrunt]

This is hearsay but I was led to believe that the NZ army tested rifle grenades prior to adopting the 203 and the recoil would rattle the AUG to bits. I have read suggestions regarding the British CLAW of the nineties knocking the SA80 scope out of zero. But the 203 is said to do that to the standard scope on the AUG as well, although I never experienced that.

The French, long-time users of rifle grenades (http://www.youtube.com/watch?v=chauN53W1tI), also seem to be moving towards UGLs.

[Compost]

This is hearsay but I was led to believe that the NZ army tested rifle grenades prior to adopting the 203 and the recoil would rattle the AUG to bits. I have read suggestions regarding the British CLAW of the nineties knocking the SA80 scope out of zero. But the 203 is said to do that to the standard scope on the AUG as well, although I never experienced that.

The following paras on rifle grenades summarize what I have been told/instructed and read over time combined with some assumptions. (Due to ignorance, the affects of gas being bled off into the cylinder during the grenade launch is largely ignored.)

Launch of a bullet-trap or bullet-through rifle grenade does include some energy simply transferred from the bullet to the grenade. However, the grenade is mainly projected by gas and that is the basic reason for the higher recoil force.

Depending on the configuration of the muzzle and/or projector, the rapidly expanding jet of gas driving the bullet out of the barrel may be initially directed upon the whole or only part of the driving surface of the grenade. Whole exposure (in a chamber with a cross-section larger than the bore) or partial exposure increasing to whole exposure as the grenade moves forward would seemingly be accompanied by a reduction in the gas pressure which was until that moment restricted to the bore. However that reduction can be almost instantaneously overtaken by an increase as the continued expansion of the gas jet is restrained by the slowly accelerating grenade.

Rifle ammunition is designed to burn propellant to initiate the movement of a bullet and spin it up to achieve a particular muzzle velocity. Irrespective of whether the propellant is fast- or slow-burning and whether that propellant is exposed and burnt at a uniform or an increasing or reducing rate, the bullet is started and accelerated by varying pressures of gas. Typically a gas pressure peak is generated early during passage of the bullet up the barrel and the bullet is stabilised although it can still be accelerating as it exits the muzzle due to an ( ‘extinguished’ or still-burning) gas jet that continues to operate but at a lower pressure than lower in the bore. To avoid violent operation of the bolt unlocking mechanism and of the bolt itself, a rifle and its ammunition are designed so that pressure in the barrel has been somewhat reduced before any gas reaches a tapping port into a recoil cylinder.

A particular feature of the rifle grenade is that it introduces another pressure peak and also adjacent high pressures that all occur close to the muzzle. Dependent upon grenade weight, that second pressure peak can be higher or much higher in a rifle than the ‘normal’ pressure peak produced when firing a single round of ball ammunition.

The time span during which the grenade-related pressures operate can be referred to as a pressure pulse. In a short-barrelled carbine that second peak will tend to reach a higher pressure and consequently duration of the pulse will be reduced.
All gas pressures generated in the barrel are also directed backward to the firing chamber and via the bolt to the bolt locking mechanism. If the intended use of a rifle or carbine includes the firing of rifle grenades, then the bolt locking mechanism must be more strongly engineered. That applies especially to the lugs of a forward locking bolt, and the receiver that houses a rear locking bolt

Additionally the second peak and adjacent pressures occur as gas is being tapped from the barrel to drive the bolt-unlocking cycle. To avoid violent unlocking it is preferable to suspend or reduce gas tapping. For example the gas regulator of a 7.62mm FAL/L1A1 SLR was routinely adjusted to close off the gas cylinder before firing a ballistite cartridge to launch an Energa AT grenade. Failure to close off often resulted in a bent piston rod.

My books on ballistics and small arms are currently packed in boxes, and this topic will be long gone before they are unpacked. So am interested to read any post that identifies an authoritative and readily accessible source, or provides detail that expands on or contradicts the above.

But in summary there is at least one good technical reason to avoid use of rifle grenades.

[Fuchs]

Keep in mind that you do not need to use heavier rifle grenades than barrel-launched grenades, and you don't need to use them at a higher velocity.

FN Bullet-thru: 320 g
40x46mm: 230-250 g

This means all higher recoil would quite by definition be an intentionally accepted by-product of higher performance.

[Compost]

Air-burst 40x53mm HV cartridge grenades and integrated FCS-fuzesetters are already available for several types of 40xmm AGLs.

A recent report claims the USMC is seeking air-burst capability for its 40mm UGLs and MGLs: see www.military.com/news/article/2011/marines-want-more-potent-air-burst-weapon.html

During the last few years Germany, Israel, Singapore and South Africa have each been rumoured to be developing FCS-fuzesetters or sights with dial-in fuzesetters for air-burst 40x51mm MV and also for 40x46mm LV cartridge grenades. So candidate systems for USMC evaluation could include several of these.

[Compost]

Last para of item 72 is misleading. Copy of the recent USMC RFI for airburst 40mm cartridge grenades is available at
https://www.neco.navy.mil//synopsis_file/M6785412I1002_PMIW_RFI_Proximity_Fuzed_Ammunition_ 13_Oct_11.docx

RFI specified proximity fuzed 40mm LV grenades to engage defilade targets between 30 and 150 metres. Ammunition to be compatible with M203 and M32 launchers without requiring any modification or addition of equipment. RFI closed on 5 Dec 2011 at 4PM.

[jcustis]

I submitted an idea to the Marine Enhancement Program a few years ago, recommending the exploration of an indirect fire sight to allow for the M203 to be employed in an IDF mode, similar to the the sling technique that has been all but forgotten.

The MEP folks said it would be pushed past Gunner Eby at that time to review, and it seems it didn't stick.