The Roles and Weapons with the Squad

[Demon Fox]

Well, now that I'm aware there is a profile page, I'll fill it out.

For everyone: hello, I am a retired 18Z (plus 18F and 18E). I live in Colorado Springs and currently doing contract work. I find the blogs and stories here in the SWJ very interesting and informative. I like seeing the differences in opinions and experiences.

SethB: you say you rolled your eyes at the M-240 story, but just because you didn't hear about it doesn't mean it didn't happen. My own battalion leadership suggested linking the 7.62 match to get rid of it before fiscal year turn-in, and we told them no - bad idea.

When experienced 18Bs say not to use certain ammo in certain weapons, I tend to believe them.

v/r

DF

[Ken White]

The 240 incident you cite is probably not one I know of but there have been at least two others that I'm aware of. In all those cases, there's a possibility the ammo was not causative -- could well have been simply coincidence. Lot of things can cause weapon failure, even age....

The standard pressure for 7.62x51 in US service hovers around 50K psi -- that includes the M118 Match. However, some folks buy special lot, off DODIC stuff like the special purpose M993 AP which pops at 55,115 psi. Those same guys buy some also special lot M118 for longer range usage and those can go up to 60,200 psi.

All 7.62 issue weapons are batch tested with the M60 High Pressure Test cartridge at 67.5K psi so theoretically that even 60.2K psi should be a no worries item.

Since the M240 has to be able to handle that max, the blow up may well have been caused by something else...

[Demon Fox]

OK, back to the ammo stuff:

The following is copied straight out of FM 3-22.9 (12 August 2008) Chapter 2, pages 2-35 thru 2-36:

-------------------------------------------------------
This section provides information about different types of standard military ammunition used in M16- and M4-
series weapons.

Use only authorized ammunition manufactured to U.S. and NATO specifications (Table 2-8).

Table 2-8. Authorized ammunition.

M193 cartridge –
5.56-mm, ball
Plain tip The M193 is the
standard cartridge for
field use with the M16A1
rifle.
The M193 cartridge is a center-fire cartridge
with a 55-grain, gilded metal-jacketed, lead
alloy core bullet.

M196 cartridge –
5.56-mm, tracer
Red or orange tip The M196 cartridge is
used only in the M16A1
rifle.
Its main uses are for
observation of fire,
incendiary effect, and
signaling.
Soldiers should avoid long-term use of 100
percent tracer rounds, which could cause
deposits of incendiary material or chemical
compounds that could damage the barrel.
When tracer rounds are fired, they are mixed
with ball ammunition in a ratio of no greater
than one-to-one with a preferred ratio of
three or four ball rounds to one tracer round.

M199 cartridge –
5.56-mm, dummy
Six grooves along
the sides of the
case beginning
about 1/2 inch
from its tip
The M199 dummy
cartridge is used in all
M16-/M4-series
weapons during dryfiring
and other training.
This cartridge contains no propellant or
primer.
The primer well is open to prevent damage
to the firing pin.

M200 cartridge –
5.56-mm, blank
(no projectile)
Case mouth is
closed with a
seven-petal
rosette crimp,
violet tip
The M200 blank
cartridge is used in all
M16-/M4-series
weapons.
N/A

M855 cartridge –
5.56-mm, ball
Green tip The M855 cartridge is
used in the M16A2/3/4
and in M4-series
weapons.
The M855 cartridge has a 62-grain, gilded
metal-jacketed, lead alloy core bullet with a
steel penetrator.
The primer and case are waterproof. This
round is also linked and used in the M249.
NOTE: This ammunition should not be used
in the M16A1 except under emergency
conditions, and only at targets less than 90
meters away. The twist of the M16A1 rifling
is not sufficient to stabilize the length of the
round's projectile.

M856 cartridge –
5.56-mm, tracer
Red tip (orange
when linked 4 to 1
for the M249)
The M856 tracer
cartridge is used in the
M16A2/3/4 and M4-
series weapons.
The M856 tracer cartridge has
characteristics similar to the M196 tracer,
with a slightly longer tracer burnout distance.
This cartridge has a 63.7-grain bullet.
The M856 does not have a steel penetrator.
NOTE: This ammunition should not be used
in the M16A1 except under emergency
conditions, and only at targets less than
90 meters away. The twist of the M16A1
rifling is not sufficient to stabilize the length
of the round's projectile.

M862 cartridge –
5.56-mm, short-range
training ammunition
(SRTA)
N/A The M862 SRTA is used
in all rifles and is
designed exclusively for
training.
The M862 SRTA can be used in lieu of
service ammunition on indoor ranges and by
units who have a limited range fan that does
not allow the firing of service ammunition.
If adequate range facilities are not available
for sustainment training, SRTA can be used
for any firing exercise of 25 meters or less.
This includes the 25-meter scaled silhouette,
25-meter alternate qualification course, and
quick-fire training.
SRTA can also be used for urban operations
(UO) training.
NOTES: 1. See Appendix A for use of SRTA
in training.
2. Although SRTA closely replicates the
trajectory and characteristics of service
ammunition out to 25 meters, the settings
placed on the sights for SRTA could be
different for service ammunition. SRTA
should not be used to battlesight zero
weapons that will fire service ammunition.
3. SRTA ammunition must be used with the
M2 training bolt.

M995 cartridge –
5.56-mm, armor piercing
(AP)
Conventional
brass cartridge
case
Aluminum cup sits
at the rear of the
projectile (for the
purpose of
properly locating
the penetrator
within the
projectile)
The M995 cartridge is
used by the M249
(SAW), M16/A2/A3/A4,
and M4-series weapons.
It is intended for use
against light armored
targets.
The M995 offers the capability to defeat light
armored targets at ranges two to three times
that of currently available 5.56-mm
ammunition.
The M995 cartridge consists of a projectile
and a propelling charge contained in a brass
cartridge case. The projectile is a dense
metal penetrator (tungsten carbide) enclosed
by a standard gilded metal jacket. The
cartridge utilizes a double base propellant. A
standard rifle cartridge primer is used in the
case to initiate the propelling charge.

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


You may notice that neither Mk262 Mod 0 nor Mk262 Mod 1 77 grain ammo is NOT on this authorized list of ammunition for the M16 and M4 family of rifles. SethB, you ARE correct that the 77 grain can be put through M4/M16s with documented good range and effects; however, if the Army didn't put it on the authorized list they probably had a reason. Additionally, the 77 grain is usually in such short supply that it is reserved for the unit's SPRs/Mk12s.

You'll also notice that some of the ammo is restricted when it comes to the M16A1, to include the M855 standard green tip.

As for the development of the 77 grain, below are some websites that discuss it. Most claim it was developed specifically for the SPR; a couple mention development for competition purposes (which makes logical sense). One source also mentions that USAMU indeed led the development for combat purposes.

http://en.wikipedia.org/wiki/5.56x45mm_NATO

http://en.wikipedia.org/wiki/Mk_12_S..._Purpose_Rifle

http://www.globalsecurity.org/milita...round/mk12.htm

http://www.snipercentral.com/223.htm

http://www.angusarms.com/SPR.htm

http://www.gunsandammo.com/content/b...2-mod-1?page=2

http://www.thegunzone.com/556faq-nb.html

http://www.bravocompanyusa.com/Articles.asp?ID=145

http://ammo.ar15.com/ammo/project/hist_mk262.html

http://m4carbine.net/showthread.php?t=28326



As for the 7.62x51 173 grain M118 and 175 grain M118LR match ammo: if you want to link it up and give it a shot through an M240, go right ahead. I'll be standing back behind the line when you do. :-)

v/r

DF

[Pete]

This makes me feel old. When I was a kid we bit the end of the cartridge to pour the powder in before we rammed the ball home. When the barrel was badly fouled British .577 rounds were easier to ram than the U.S. .58 stuff. No doubt JMA remembers .577-calibre from his rhinoceros-hunting safari days.

[Demon Fox]

Ken, you could very well be correct on the M240 issue. It happened in a different group than mine and word got around. My Bn leadership also suggested lining up a bunch of sniper rifles and burning the ammo. OK, we had over 53,000 rounds of M118 7.62x51 match ammo - you do the math! I told the commander that he would have to buy a bunch of new sniper barrels after we were done! We wound up just eating the ammo on our FY report. There was just no legal or safe way to get rid of it.

I once witnessed an M240 have an accidental discharge due to poor maintenance. It was new guy on our team using another team's MG at a convoy live-fire range. We broke apart the M240 to see if there was mechanical malfunction to explain the AD. When we opened the feed tray the metal was literally peeling off from rust. I was furious at the blatant neglect and our new guy was cleared of wrongdoing.

Here is the list of authorized M240B ammo from FM 3-22.68 (Jul 06):

The M240B machine gun uses the following types of ammunition. See also table 3-3:

􀁹 Cartridge, 7.62-mm Ball M80—for use against light materials and personnel, and for range training.

􀁹 Cartridge, 7.62-mm Armor-Piercing M61—for use against lightly armored targets.

􀁹 Cartridge, 7.62-mm Tracer M62—for observation of fire, incendiary effects, signaling, and for training. When the gunner fires tracer rounds, they mix with ball ammunition in a ratio of four ball rounds to one tracer round.

􀁹 Cartridge, 7.62-mm Dummy M63—for use during mechanical training.

􀁹 Cartridge, 7.62-mm Blank M82—for use during training when simulated live fire is desired. The gunner should use a BFA to fire this ammunition.

v/r

DF

[SethB]

Not particularly concerned about shooting heavy OTMs through a short barrel. I've done enough of it.

It may not be on the approved list, but it wasn't designed for combat use and the fact that it was eventually approved for anything is a tribute to a few people that shepherded it through the system.

See Ken's post for a coherent discussion of pressures.

And for M855, you can't shoot it through an M16 or M16A1 because the 1:12 twist barrel wont stabilize the longer bullet.

M4s and recent M16s have a 1:7 barrel, although 1:9 will stabilize M855 just fine.

[Demon Fox]

LOL, Pete:

A few months ago I was reading an article in a hunting magazine (can't remember which one) and there was an Africa safari story in there. The author described the standard light, medium, and heavy rifles taken on safari. I was laughing, because in this case the "light" gun was something like a .458, the "medium" gun was a .600, and the "heavy" gun was a friggin' .700 with a 1,000 grain bullet!! The article had a pic showing the author test firing the .700 . . .

[Fuchs]

'59 document on ranges

http://www.cfspress.com/sharpshooter...le-ranges.html

[Ken White]

It colored the thinking of the Army -- to no good end, consumed massive amounts of research and development money and produced -- nothing.

Other than harm.

It was a farce and it has adversely impacted my thinking about about statistical analyses by academics on combat matters since it hit the street in the mid-50s. The '59 and 60s date mentioned are from the time it was declassified, the study was completed in the early 50s.

Combat is not a numeric exercise and 'statistics' gathered invariably reflect specifics at a time and place -- those may or, more likely, may not be applicable at another time and place with different people doing ostensibly the same thing in a setting only slightly modified. Numbers and metrics should be used to assess combat efforts with great caution.

This study was also the lever for much US Army foolishness in attempting to use technology to compensate for poor training, a disastrous failure that is still entirely too prevalent.

[Fuchs]

This study was also the lever for much US Army foolishness in attempting to use technology to compensate for poor training, ...

To be honest, that became a hallmark as early as '42, then rooted in the lacking numbers of experienced leaders.

[Firn]

Combat is not a numeric exercise and 'statistics' gathered invariably reflect specifics at a time and place -- those may or, more likely, may not be applicable at another time and place with different people doing ostensibly the same thing in a setting only slightly modified. Numbers and metrics should be used to assess combat efforts with great caution.

I just wonder how the study could get so bad markmanship results at 300 yards, and such a small difference between the experts and standard shooters.

[Pete]

This study was also the lever for much US Army foolishness in attempting to use technology to compensate for poor training, a disastrous failure that is still entirely too prevalent.

True, but that's always been the American way. There were the Spencer rifles and carbines during the Civil War and the Pedersen Device idea during War I.

If I recall correctly the statistical study Fuchs posted was cited as one of justifications cited for adopting the M16 in 1965. At the time when the M14 vs M16 thing was going on I've also gotten the impression that McNamara had a big grudge against U.S. Army Ordnance, particularly its sprawling empire of depots and installations, which he wanted to convert into DoD facilities. I also read something to the effect that the comparative shoot-off by Ordnance between the M14 and the FN was then regarded at the DoD level as having been rigged in the M14's favor. The old Army Ordnance gave us some true subject matter experts like Julian Hatcher but I fear they had begun to think they had all the answers about everything. It could have been sort of a "Pride comes before a fall" kind of thing.