Sinister posted:

Jeff, in your feed ramp damage article the Army's photos stink of something bad.

The photo with the ripped-up left-hand side ramp and lower left quadrant locking surfaces shows the right ramp apparently undamaged:

This photo shows what appears to be a barrel with M16 rifle barrel extension fitted into an upper receiver with what looks to be M4 carbine ramps.  Damn near ANY ammunition would show/make the same damage if all rounds came out of new OR modified feed angle magazines:

Yes, picture 2 looks like the gun MIGHT have mismatched (Case 4 below) feed lips between barrel extension and upper.

Case 1:  M16 Extension/M16 receiver - GO

Case 2:  M4 Extension/M4 receiver - GO

Case 3:  M4 Extension/M16 receiver - GO (but not optimal)

Case 4:  M16 Extension/M4 receiver - NO-GO

Jason -------------------------------- "Consumer, how many times have you hankered for vegan mayonnaise only to realize you're not man enough to open the jar?" -- Bucky B. Katt

We had several allied units come to our ammo point to draw 5.56 and 7.62.  The system seems to work all right.  UK 5.56 ammo is under-powered in our guns (NOT to be used in combat).  Our 7.62 was hot in Japanese T64 rifles (which were designed for lower-pressure ammo) if you didn't use the standard-pressure setting on the gas block.

stukas87 posted:

I doubt it, Countries like England who have fought by our side the longest in the Middle East still use their own 5.56.  The whole NATO Compatible thing sounds good on paper but has never truly been implemented.

Imagine, we will be using HK G36 for a long time while Germans are replacing them because of hot related accuracy problems. I don't expect new updated ammo for a while.

Joined: 30DEC08      Location: SPAIN

Take care, keep safe, stay frosty, brother!

tirotactico.net

My unit finally got to use M855A1 (M4A1) and M80A1 (M240L) for our AT and seemed to function well, but still got Green Tip for our M249's. Only issue I saw was that the projectiles seemed a cunt hair too long to use stripper clips to load our USGI aluminum mags easily.

From everything I've seen on YouTube these offer a pretty substantial improvement in terminal and barrier penetration, maybe arm chair gun nuts will finally STFU about getting a 7.62 MBR to replace the M4... yeah yeah I know, wishful thinking.  

PRAISE THE FALLEN

SSG Kevin Roberts KIA 7-May-08         SPC Peter Courcy KIA 10-Feb-09

1Lt Nick Dewhirst KIA 20-July-08          PFC Jason Watson KIA 10-Feb-09

CPL Charles Gaffney KIA 24-Dec-08

 

Joined: 2/21/04          Location: Seattle,  WA

Sinister posted:

Jeff, in your feed ramp damage article the Army's photos stink of something bad.

The photo with the ripped-up left-hand side ramp and lower left quadrant locking surfaces shows the right ramp apparently undamaged:

This photo shows what appears to be a barrel with M16 rifle barrel extension fitted into an upper receiver with what looks to be M4 carbine ramps.  Damn near ANY ammunition would show/make the same damage if all rounds came out of new OR modified feed angle magazines:

So I feel I should clear some things up.

The first photo is mine, and nothing is damaged. It's whiteout, and it was done to show where M855A1 strikes the feed ramps during cycling from a variety of magazines. That little black dimple near the top center of the left feed ramps??? That's where the bullet tip struck the feed ramps during feeding, this imagine was from either the M3 or EPM....I can't remember which.

Originally the post was made on arfcom by me.

https://www.ar15.com/forums/ar...y_photos_/17-684147/

It was not meant to be definitive or scientific, but just a rough demonstration of how magazines fed M855A1, and where the hardened tip strikes. I did the whiteout bit because it was requested to better demonstrate the bullet's path during feeding.

The issue is this. The 82nd Small Arms Master Gunner saw my post, and took it and my photos and ran with it on the internet. It was then picked up by other publications like the one Chris Bartocci runs, and since the 82nd took my photos and took the context out of them, they've been used to show how bad M855A1 feeds.

Truth is, it couldn't be farther from the truth. See, when I did my little test, every magazine fed the round. Sure some were lower on the feed ramps, and came closer to striking the aluminum M4 cuts....but at the end of the day none of them did.

Now this was important, because if you had one of the lower feeding magazines like the Tan Follower GI mag, once it gets worn out and it doesn't feed as quickly, it will run into issues of striking the aluminum lower faster than others. This however isn't an issue with new magazines.

End of the day, the M27 is the only gun that has immediate issues with M855A1 and requires 100% use of M3 Pmags to not receive damage.

This is solely due to using no M4 cuts in the receiver and M16 feed ramps in the extension, as well as using a nearly flat chamber face forcing cone and the cyclic rate of the M27 being around 200-250rpm faster than the M4.

The issue just isn't there in the M16 and M4, unless you're running beat to shit mags that barely feed as is.

 

Whiteout very interesting and thanks for commenting..Yes your pics I've seen sighted and used on numerous sites and there's no explanation of white out. We all thought it was chipped teeth. And they are the only photos I can find from the military so you've actually done a good thing I think. Even though a lot of people might have used it as a negative against M855A1.

stukas87 posted:

Whiteout very interesting and thanks for commenting..Yes your pics I've seen sighted and used on numerous sites and there's no explanation of white out. We all thought it was chipped teeth. And they are the only photos I can find from the military so you've actually done a good thing I think. Even though a lot of people might have used it as a negative against M855A1.

Here's a couple of official images from Aberdeen. These were done with the Tan follower GI mags, even though there is a small bit of wear on the M4A1, it's minimal. The M27 did suffer however.

https://imgur.com/a/1PdasU9

I had two teams out all week doing M16 and M4 Known Distance prep and practice for the Army Championships in March.  

M855A1 continues to impress me with how much better it is, overall, than Green Tip.  If there's little or no wind it makes very gratifying tight groups at 400 and in, even from standard M4A1s (with ACOGs).

We're swapping out our M16A2s for A4s shortly, and I'm hoping M855A1 out of the longer musket with ACOG will do well out to 500 yards.

It dings the hell out of AR500 plates at 200 yards.

You should see how it tumbles in people

I brought an 18" MSTN upper to OEF and M855A1 was grouping well at 500. Hold-off's were also easier compared to M855.  You'll need to get the subtensions for the ACOG's from Trijicon - they were supposed to make an M855A1 specific model but never did. I believe with the right argument / hard data that could change, but such a small population of the force would see benefit from it that it'd likely just be a SOCOM thing.

We were told accuracy standard was 2 MOA, but we regularly grouped 1.5-1.75" with most lots.

Good luck to your teams competing, Sir!

"I came here for one reason: to attack and keep coming.- Ultimate Warrior

 

"Americans don't deserve America." - Timmy

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