Interesting perspective on M855A1 by retired SF

[okie]

Never understood that myself.

You can get 70gr TTSX loads for cheaper, why not do that?

Might have some increased performance over FMJ in window glass and car skin, but it's not going to do what M855A1 can do. You're talking about a copper HP, vs. a hardened steel penetrator. A1 can defeat a lot of armor that solid copper bullets can't.

You know, that also makes me wonder about A1's performance against soft armor at long range. IIIA will stop just about any FMJ when it falls below about 2k fps, so at 300 yards or so it starts becoming pretty effective. But given the sharp tip on A1 it might just sail right through even at much lower velocities. Soft armor performs very poorly against anything sharp. Even an arrow fired from a longbow will sail right through it.

[sinister]

So if you had to pick a specific round to meet all requirements (CQB, distance, penetration, target maybe has body armor) which of the available rounds would you choose? Basically the uber 5.56 round. Not for one mission, but a round that optimally covers just about all scenarios. Jungle, Arctic, distance, barriers, etc. Might come up shorter in some categories than others, but a best all-around choice.

Include M855A1 in your list of choices as it is somewhat (albeit expensively) available to civvies.

If I was Chairman of the Joint Chiefs and we had a North American tungsten source, I'd say standardize M995 Armor Piercing as the Army load.



It is precise, heavy (doesn't get blown around by wind nearly as much as 55 and 62-grainers, has enough inertia to go 600 yards easy at sea level in 95-degree heat, enough ass to hurt someone's feelings in armor, and punches deep through tissue), and works in legacy weapons we have in hand, right now, today, NATO compatible. Like M855 and A1 it'll tear up silhouettes and kill house steel.

[vicious_cb]

If I was Chairman of the Joint Chiefs and we had a North American tungsten source, I'd say standardize M995 Armor Piercing as the Army load.



It is precise, heavy (doesn't get blown around by wind nearly as much as 55 and 62-grainers, has enough inertia to go 600 yards easy at sea level in 95-degree heat, enough ass to hurt someone's feelings in armor, and punches deep through tissue), and works in legacy weapons we have in hand, right now, today, NATO compatible. Like M855 and A1 it'll tear up silhouettes and kill house steel.

No need, when A1 was in development it was stated early on that the design be modular meaning the steel penetrator could be swapped out for a tungsten one. They even developed a new sintering process to mass produce tungsten penetrators. Then they did the math and realized that 1 year of M855A1 production would exhaust the entire strategic reserve of tungsten, they scrapped the idea. General issue tungsten core ammo is a pipedream unless we can source more tungsten, and guess where the largest reserves of tungsten are located...

[MikhailBarracuda91]

No need, when A1 was in development it was stated early on that the design be modular meaning the steel penetrator could be swapped out for a tungsten one. They even developed a new sintering process to mass produce tungsten penetrators. Then they did the math and realized that 1 year of M855A1 production would exhaust the entire strategic reserve of tungsten, they scrapped the idea. General issue tungsten core ammo is a pipedream unless we can source more tungsten, and guess where the largest reserves of tungsten are located...

China

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[1168]

If I was Chairman of the Joint Chiefs and we had a North American tungsten source, I'd say standardize M995 Armor Piercing as the Army load.



It is precise, heavy (doesn't get blown around by wind nearly as much as 55 and 62-grainers, has enough inertia to go 600 yards easy at sea level in 95-degree heat, enough ass to hurt someone's feelings in armor, and punches deep through tissue), and works in legacy weapons we have in hand, right now, today, NATO compatible. Like M855 and A1 it'll tear up silhouettes and kill house steel.

Gross. No upset. Tungsten resource.

Unlike 855 and A1, it sails straight through target steel in my experience.

I did keep a mag (de-linked) of it in ar Ramadi to deal with vehicles.

[sinister]

I can't find the youtbe video where a Swedish or Norwegian squad shot up a BRDM with their 416s.

Side of that vehicle may as well have been a cardboard e-type.

I'd rather have more shoot-through hits with no upset than half a mag of misses.

[1168]

I can't find the youtbe video where a Swedish or Norwegian squad shot up a BRDM with their 417s.

Side of that vehicle may as well have been a cardboard e-type.

I'd rather have more shoot-through hits with no upset than half a mag of misses.

That is one technique for dealing with light armor. I can’t say that its wrong.

[lysander]

Liberty Ammunition sued the federal government for patent infringement and breach of contract in regard to M855A1.




....

They lost that case.

1. The Officer in question did not have the authority to commit the USG to any contractual obligations. If you are dealing with the military, remember that. Not all Officers, regardless of rank, are empowered to commit the USG to a binding contract.

2. The design of the M855A1 did not infringe on the patent's claims. Remember that, too. Just because it looks similar, does not automatically mean infringement, what matters it what you claim in the body of the text as the improvement.

[lysander]

Anyone have an idea when they downloaded the M855A1 to it's current level?

MIL-DTL-32338A with Amendment 5, dated 16 February 2017, changed some things regarding the chamber pressure, but I would not call it “downloading” in any way, shape, or form.

1. The maximum average chamber pressure was reduced 500 psi.

2. The average plus three standard deviations remained the same at 66,000 psi

3. The maximum average chamber pressure at extreme temperatures was changed from “the average chamber pressure at 70 degrees plus 7,000 psi” to just “shall not exceed 67,000 psi,” but the average chamber pressure at extreme temperature plus three standard deviations was INCREASED to 71,000 psi. That’s 4,000 psi higher than before.

All other parameters, velocity, port pressure, etc, remained the same.

St Marks may have tweaked the propellant formula to keep the average pressure down away from the permitted maximums, but the requirement limits are largely the same.

[lysander]

The mil-spec referenced does not specify “a 6.8” group at 600 yards”. The mil-spec for M855 calls for an average vertical standard deviation and an average horizontal standard deviation of 6.8” at 600 yards. The average vertical and horizontal standard deviations are completely different metrics of measuring the radial dispersion of shot groups than the extreme spread. Also, the referenced mil-spec is not for the “M16A2, with green-tip or M855.” The referenced mil-spec using the average vertical and horizontal standard deviations is for M855 fired from machine-rested, bolt-action heavy test barrels.

MIL-DTL-32338A with Amendment 2, dated 23 April 2014, changed that.

The requirement was changed to: the average standard deviation, both horizontal and vertical shall not be greater than 6.3 inches at 600 yards but kept the 1.8 at 200 yards requirement.

With Amendment 4, dated 19 June 2015, the 200 yard figure was reduced to 1.6 inches.

So, currently the requirements are that the horizontal and vertical standard deviation:

600 yds = 6.3 inches
200 yds = 1.6 inches