"Testing the M855A1"

[R0N]

Mk318 is an interim solution for the Marine Corps, it is not the replacement for M855

[TehLlama]

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.

[R0N]

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]

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?

[markm]

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.

[TehLlama]

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.

[markm]

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.

[TehLlama]

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.

[opngrnd]

...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]

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.