Mechanized Infantry Perceptions 2010

[gute]

I'm currently reading the book Carnivore which is about a cav scout soldier and his units fight during the invasion of Iraq. The author writes about engaging T-72 tanks with the Bradley 25mm depleted uranium or DU rounds and killing the tanks. My question has to do with the Ground Combat Vehicle and arming it with a 25mm cannon and not something bigger. Could these type of experiences in Iraq had something to do with the idea of arming the GCV with a 25mm cannon? Or, is it simply about going with the status quo? Do U.S. Army armor thinkers believe that in the future the type of armor we are most likely to face will be Soviet design like the T-72 and the DU rounds will be sufficient to destroy the vehicles. The author did say that if the T-72 hit his Bradley with its 125mm the crew would be toast - no suprise there.

[Fuchs]

My question has to do with the Ground Combat Vehicle and arming it with a 25mm cannon and not something bigger. Could these type of experiences in Iraq had something to do with the idea of arming the GCV with a 25mm cannon?

Other armies went from 30 to 40 caseless (UK), from 20 to 30 (Germany), added a 100 mm next to their classic 30 mm (Russia) or kept using something in the 23-40 mm range. Most IFV purchases of the last few years appear to have been about 30-35 mm main guns.


I suppose the U.S.Army simply stuck with what's established in its training and ammunition stock system. I have yet to see or meet any source claiming that 25 mm is optimal. The problem is that the autocannon calibre choice is a choice between the devil and the deep sea. It's unsatisfactory in some regards, no matter what.
25 mm does not chew or bite easily through walls unless you use expensive APFSDS, and that's messy in infantry support because of all the sabots. 35 or 40 mm doesn't allow you to carry many rounds. Telescopic ammo such as used by the CTA 40 is more compact, but you could still carry more if you stuck with a smaller calibre.

[jcustis]

I would offer that there are clear distinctions between an infantry fighting vehicle, capable of killing comparable vehicles with its main cannon or ancillary ATGM, and an infantry support vehicle, capable of rendering support in any sort of built-up environment.

One needs to consider how the US Army has organized and equipped itself in the past to accomplish those two discrete tasks, before asking the question about caliber size for any main cannon.

When the Bradley was developed, side saddle TOW launchers were emplaced in the design, but the unit organizations still M1 tanks mixed in to provide the wall-busting support required, and the development of 120mm ammunition has followed an arc aimed at penetrating and reducing heavy cover.

As the Army transitioned to the Stryker and its remote weapon system of no larger than 40mm AGL or .50 HMG, it bought the 105mm Mobile Gun System variant to provide infantry support within those formations, since the M1's 120mm main gun was lost.

The US has never had a one-design-fits-all mindset when it comes to mechanized infantry operations, like the Russians have through the BMP-1 through -3 series of IFVs, and there is some inherent flexibility (and for sure some weaknesses) from that approach.

It seems the US Army stuck with what was in its training and ammunition system not so much out of a desire to avoid additional cost, but because that system and combination of capabilities has proven capable enough to meet the infantry's needs. If it were found woefully wanting, there would for sure be pressure to adjust and implement new systems, but the current crop of tools is generally adequate and the US Army mindset has recently trended towards C4ISR upgrades before ordnance changes.

I would guess that we won't see a main cannon for another couple of generations.

[jcustis]

I'm currently reading the book Carnivore which is about a cav scout soldier and his units fight during the invasion of Iraq. The author writes about engaging T-72 tanks with the Bradley 25mm depleted uranium or DU rounds and killing the tanks. My question has to do with the Ground Combat Vehicle and arming it with a 25mm cannon and not something bigger. Could these type of experiences in Iraq had something to do with the idea of arming the GCV with a 25mm cannon? Or, is it simply about going with the status quo? Do U.S. Army armor thinkers believe that in the future the type of armor we are most likely to face will be Soviet design like the T-72 and the DU rounds will be sufficient to destroy the vehicles. The author did say that if the T-72 hit his Bradley with its 125mm the crew would be toast - no suprise there.

It turned out to be abandoned the next day when we inspected it, but one night my gunner picked up a BMP-2 in his sights at about 800m, right after the vehicle came to a halt. He hit it with APDS-T (the non-depleted uranium AP round) and the penetrators still went through it like a hot knife through butter. It was a flank shot and not against the frontal armor, but I have no doubt we would have killed it just the same.

I've heard anecdotes of 25mm killing T-55s, but not -72s (or at least I never believed them).

One funny story was when one of our scout team leaders fired a HEAA round from a 83mm SMAW against the flank of an abandoned T-72 at a couple hundred meters. The first round flew over the turret by an inch or so because he failed to adjust a sight setting. The second round hit square in a sponson box, detonated, but barely scratched the hull he was trying to penetrate.

The whole situation was remedied when an industrious young combat engineer corporal and his two subordinates crawled inside with a satchel charge. The resulting explosion of the explosives, and every round and bit of propellant inside the hull, sent the turret somersaulting through the air by a hundred feet or so. This was followed by a dejected scout climbing back aboard his vehicle to face the ribbing of the crew.

[Fuchs]

I'm sure you meant "depleted uranium". It makes no sense to use non-depleted uranium for such a purpose.


T-55s have late WW2-like side armour and rear armour is even weaker. All MBTs have ballistic windows - sights, hatches, turret ring, barrel - and can occasionally be penetrated by really weak penetrators.

External equipment - including CITV and externally stored personal items - is even more generally vulnerable.

The ability to penetrate should thus not be judged by anecdotes, but by the ability to penetrate
front turret
upper and lower glacis
side turret
side hull

25 mm is quite unsatisfactory even against a T-55 if you look at these. Lower hull sides are the only large surfaces which an autocannon can penetrate reliably, and I doubt a 25 mm APDS or APFSDS could do so even at a perfect angle.


Basic BMPs are notoriously thin-walled. Their protection is APC-like; they keep most bullets, most fragments and AP mine effects out and that's about it.
Upgraded BMPs on the other hand can be loaded with so much extra protection that even 30 mm APFSDS and AT4s would not penetrate front or sides.

[jcustis]

Okay, yes--the APDS round that is not the one with a penetrator formed from depleted uranium. That is what I meant, though most can probably infer the point I was getting at.

To your point about 25mm and inadequacy against a T-55 (or any tank for that matter), it shouldn't be employed against a T-55, so inadequacy is irrelevant. If a BMP is approaching tank weight and protection, don't bother trying to kill it with an IFV direct-fire weapon. Get a Javelin, or a tank.

I guess you could say this goes back to gute's question about sticking with a 25mm, especially in light of the trend in BMP (and comparable AFV/IFV) protection. There is no way threat capabilities are ignored, but rather planners are looking at smarter ways to counter the threat. It also goes back to the point about trying to kill a monster IFV with another IFV. If the enemy wants to push the armor/weight boundaries, maybe we should just let them, but remain flexible with our task organization.

Vehicles look great when they are all pristine in a glossy manufacturer's pamphlet or an edition of Janes, but in the field, amidst the muck and the mire, advertised capabilities become an entirely different proposition. There are penalties to pay with the protection.

Ona slightly related tangent, has anyone been catching Russian-narrated videos of Syrian armor in the attack, or of the absolute havoc being wrecked on the tanks when they let their security down and the insurgents get to employ RPG-29s? Eye-opening for sure...

[gute]

Ona slightly related tangent, has anyone been catching Russian-narrated videos of Syrian armor in the attack, or of the absolute havoc being wrecked on the tanks when they let their security down and the insurgents get to employ RPG-29s? Eye-opening for sure...

Youtube?

[gute]

I watched a Youtube video of a Syrian tank hit by a RPG-29. It looked like the tank was hit on the very top of turret or the deck right behind the turret. Scary stuff. Smoke coming out of the hatches and the gun and then a flame shootin 30 feet in the air. I can't believe one dude got out or he was standing outside of the tank near the rear.

[jcustis]

On another forum I frequent, quite a few tankers ran the vid back and forth in slow motion. They agreed that the guy seen holding his charred arms in the air to his sides was previously inside the turret area (yup, with the hatches closed). When the round hit, the detonation blew hatches open and the tanker out of the vehicle.

The plume of fire rushing out is the propellant of the main gun's rounds burning. That's one of the design limitations of the T-72. It's going to go up like a Roman candle if that stuff is ignited, and it is susceptible to lighting because the semi-combustible cases are exposed at the bottom of the turret basket.

That guy must have died an especially gruesome and painful death.