View Full Version : "Testing the M855A1"
Haven't read all that much about the "good vs bad" of this cartridge, but apparently it puts a lot of wear on M4's:
http://www.americanrifleman.org/articles/2014/5/21/testing-the-army-s-m855a1-standard-ball-cartridge/
SeriousStudent
01-17-15, 14:49
Moved thread to the "Reloading and Ammunition" sub forum.
The port pressure with M855 in an M4 is already quite a bit higher than that in the twenty-inch M16---and they want to jack it up another 50%? Yikes.
daddyusmaximus
01-17-15, 17:57
Haven't read much on this round either, and being retired for a while, I've never shot it. Still, I'd like to get my hands on a case of it. I like the fact that it will yaw faster and be more effective on skinny targets, but as I said, I'm retired, so I'm not too worried about "skinny" targets here in the states... Now the better steel penetrating ability would be a good thing to have in a 5.56.
The port pressure with M855 in an M4 is already quite a bit higher than that in the twenty-inch M16---and they want to jack it up another 50%? Yikes.
Yeah. I'd love to get some of these bullets to load up. But I'd never fire this round in any of my guns.
daddyusmaximus
01-18-15, 12:59
I am thinking this would be a good round in my SBR. It's built around an Arms Tech Compak 16 upper. The gas trap system they use should be able to handle this load well.
Haven't read much on this round either, and being retired for a while, I've never shot it. Still, I'd like to get my hands on a case of it. I like the fact that it will yaw faster and be more effective on skinny targets, but as I said, I'm retired, so I'm not too worried about "skinny" targets here in the states... Now the better steel penetrating ability would be a good thing to have in a 5.56.
There was some gel test online that were promptly removed, by some government entity. The guy posted them on tos, and they were gone in less than 48 hours. The way the steel is inserted into the all copper base it looks like a solid copper vmax with a steel tip. It is supposedly not yaw dependant. The steel tip acts like the poly tips on varmint rounds.
I wish I would have saved the gel pics. I would like to just get the bullets like markm said. I would never fire the loaded ammo, I dont even like m193. So if 855a1 is as over pressure as has been reported I will stay away. To many great bullets available to us as reloaders, to put the extra wear on my personally owned firearms.
I wonder what it'd do to your bolt life when fired suppressed in an issued weapon...
"Overall, it was found that M855A1 is more accurate than the old green-tip, but capable of even better accuracy when fired from a 1:9-inch twist barrel."
Maybe there's something to be said for the 1:9 after all.
USMC_Anglico
01-24-15, 15:48
Round beats the hell out of the guns. It is no better than M855 in the real world. Now that the Army lost the patent infringement lawsuit maybe they will go to wider issue of Mk318 a much better round, USMC already got smart about that.
Mk318 is an interim solution for the Marine Corps, it is not the replacement for M855
Most of the hardware we've ever run for real as a second land army or an amphibious force are all interim solutions for a different intended goal - it's better than M855 AND M855A1, cheaper than the latter, and can be acquired in quantity easier than 70gr TTST Brown Tip, not to mention also meets the most critical design criterium M855A1 sought to answer by being a lead-free projectile... turning the final M855A1 load into a poor-man's HPT Proof round in order to meet terminal ballistics requirements is basically endemic considering everything wrong about the defense acquisition process, and the final result shows it because it sucks. Considering how much 'Joe Placebo' positive effect one should have anticipate after wide fielding, the lack thereof tells me everything I need to know that still ordering it in bulk when Mk318 is available (and not in a legally ambiguous purchase/royalty situation) and cheaper is basically a fraud/waste/abuse scandal that flies under the radar because SME's seem to be too easily drowned out by terabytes of unintelligent powerpoint presentations.
The Marine Corps is already working with the Army to fix the fouling problem and once that is done will adopt the M855A1
I am not sure there was much of a placebo effect when Mk318 fielded having read the AARs and studies of the units that got it and eventually that lead to the Marine Corps senior leaders to not adopt it as our round.
RustyKnifeUSMC
02-09-15, 16:14
Yeah. I'd love to get some of these bullets to load up. But I'd never fire this round in any of my guns.
I'm assuming this is being caused specifically due to the new powder being used (which has not been identified as far as I know) and not the design of the bullet?
I'm assuming this is being caused specifically due to the new powder being used (which has not been identified as far as I know) and not the design of the bullet?
The pressure they're using is too high. The powder is probably fine, and the bullet is probably fine, but the load is too hot.
The powder is probably fine, and the bullet is probably fine, but the load is too hot.
This makes me slightly concerned that the bullet may not be totally fine, or they're trying too hard to match an existing inventoried BDC - otherwise they'd be using a more sane chamber pressure loading... that doesn't seem like the sort of contract requirement that the good idea fairy gifts over without some help, which tells me there's something that load wasn't accomplishing until they started driving it stupidly hard with that higher quantity powder loading.
Well the bullet is certainly gobbling up a bunch more of the internal case capacity. It's a longer bullet, and you can't extend the OAL of the round... so it's back into the case. There's certainly an amount of velocity loss potential when you reduce case capacity.... to the only way to get it back is to crank up the pressure.
Well the bullet is certainly gobbling up a bunch more of the internal case capacity. It's a longer bullet, and you can't extend the OAL of the round... so it's back into the case. There's certainly an amount of velocity loss potential when you reduce case capacity.... to the only way to get it back is to crank up the pressure.
That actually makes a lot of sense - considering that it'll need to function out of 10" barrels, the longer round is going to have to be spun up to higher RPM to stabilize, and with reduced case volume it does probably need to be a 'spikier' pressure delivery to deliver adequate velocity for shorter URG packages, which means it's a pretty high initial chamber pressure (and probably a considerable step up in throat erosion rate)... I still am stuck on 'why not just use Mk318Mod1 or a derivative thereof', since it seems to have met verification and validation to a higher standard set while being a lower cost deliverable.
...or they're trying too hard to match an existing inventoried BDC...
I was under the impression BDC played a part. I doubt they'd scrap their entire inventory of ACOGs, etc, and start over just for a new round.
InfiniteGrim
02-13-15, 23:58
For all the M855A1 hate.... I can tell you that in gel, it was the best performing 5.56 I have EVER seen. Better than the self defensive ammo out there too.
I posted my results on here and AR15.com, but after a call from ATK/Pentagon it was taken down and I had to delete it from everywhere I posted it.
kaltesherz
02-17-15, 15:51
It performs better than M855, I think most can agree on that- but is it worth the trade off of damaging / wearing out weapons at a much faster rate? I'm with TehLlama on just using Mk318, but of course the Army won't because that actually makes sense.
As a side note, this is yet another reason my AR500 armor is a bad idea. When M855A1 becomes common to stateside units, inevitably rounds will be "acquired" and make their way into private hands.
For all the M855A1 hate.... I can tell you that in gel, it was the best performing 5.56 I have EVER seen. Better than the self defensive ammo out there too.
I posted my results on here and AR15.com, but after a call from ATK/Pentagon it was taken down and I had to delete it from everywhere I posted it.
I saw your test before it was removed, and it was very impressive. Your test was what I was referring to in an earlier post. I just forgot your screen name.
kaltesherz
02-17-15, 18:46
I saw your test before it was removed, and it was very impressive. Your test was what I was referring to in an earlier post. I just forgot your screen name.
I missed the earlier test, can anyone (like the original poster) give a Cliff Notes version about the results?
I know it works well on real targets. Very well.
It does everything they say it does. It is hard on guns but with Uncle Sam footing the bill, and the M4A1 upgrade, I give it 2 thumbs up.
That said, I am not sure about running vast amounts through something I have to pay for though.
kaltesherz
02-17-15, 19:43
and the M4A1 upgrade, I give it 2 thumbs up.
How does the M4A1 upgrade mitigate the higher chamber pressures? It's just a more consistent trigger and a heavier barrel, I don't see how that would keep parts from wearing out at an accelerated rate.
I'm all about increasing lethality but not at risk of durability and reliability. The Army isn't know for it's stellar weapons maintenance when it comes to round counts...
The H2 buffer helps. And the heat is transferred better with the A1 profile. This doesn't help with the main problem with the M855A1 round though. That would be wear from the penetrator hitting the chamber on feeding.
I know the pressures are high and its rough on bolts. That is being addressed.
Units will be using it stateside soon, but it has been used for a few years in combat and I have heard of no issues with it with the H2 or higher buffer and I fired a couple thousand rounds on my last deployment of the 855A1 with no issues. Only time will tell if we truly see massive failures. My guess is no.
On rifle-length weapons, I would imagine that the wear would be slightly less. Accurate?
On rifle-length weapons, I would imagine that the wear would be slightly less. Accurate?
Probably so. At least bolt breakage would be less as is currently reported with regular M855.
I'm neither an armorer nor an expert, but seeing how often gear is already dealt with in a "use it till it breaks and fix it when it does" manner, I wonder if it will make all that big a difference. If things are replaced as they are broken, will it matter in the bigger picture (think Army wide) that they are broken and replaced more often? Not that I've never seen weapons deadlined and waiting for parts.
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