Big Army Changes Barrel Wear Criteria for M855A1 Ammo - M14 Forum

M14 Forum


Big Army Changes Barrel Wear Criteria for M855A1 Ammo

This is a discussion on Big Army Changes Barrel Wear Criteria for M855A1 Ammo within the M16 AR15 forums, part of the Rifle Forum category; The Army has already introduced a new magazine to reduce wear to the M4 Carbine family upper receiver when shooting M855A1 ammo with the exposed ...


Go Back   M14 Forum > Rifle Forum > M16 AR15

9Thanks
Reply
 
LinkBack Moderator Tools Display Modes

Old March 5th, 2017, 07:05 PM   #1
Old Salt
 
nicholst55's Avatar
 
Join Date: Nov 2004
Location: Daegu, Korea
Posts: 1,703
Big Army Changes Barrel Wear Criteria for M855A1 Ammo

The Army has already introduced a new magazine to reduce wear to the M4 Carbine family upper receiver when shooting M855A1 ammo with the exposed steel tip. It changes the feed angle slightly to eliminate wear to the feed ramps of the upper receiver. Now the Army has revised barrel wear criteria for the M4 and M4A1 when firing M855A1, or predominantly M855A1. The barrel erosion gage can now slide into the barrel down to the hole for the tag at the end of the gage, a change of some 2.3" on the gage! I'd call that pretty significant. Essentially, you now wash out the barrel when the tag hanging on the gage prevents the gage from sliding completely through the barrel!

A new gage is being developed. Wonder what kind of accuracy can be expected when a barrel is just short of being unserviceable (worn out)? I'd say pretty dismal!

Note that this change only applies to M4 and M4A1 carbines, either shooting solely M855A1 or predominantly shooting M855A1 ammo.

Thanks from bfoosh006 and russ0861
nicholst55 is offline  
Remove Ads
Old March 7th, 2017, 01:14 PM   #2
Old Salt
 
bfoosh006's Avatar
 
Join Date: Jun 2007
Location: NW
Posts: 1,316
Wow.... I wonder what the justification is for such stupidity !?

By chance... do you have a link to where you saw this info ?

bfoosh006 is offline  
Old March 7th, 2017, 01:50 PM   #3
Old Salt
 
lysander's Avatar
 
Join Date: Apr 2015
Location: North Carolina
Posts: 1,761
Before we start calling the guys and/or gals at Pic-a-ninny idiots . . .

There have always been two criteria for a worn out barrel in the Army:

1) group size over 7 inches at 100 yards, and

2) a velocity drop of 200 fps or more.

The throat erosion gauge has always been just to estimate of the velocity loss, group size can be determined empirically without fancy equipment by the unit.

All this tells us is M855A1 can stand a lot more throat wear before the velocity drops below 200 fps.

Thanks from RDS
lysander is online now  
 
Old March 7th, 2017, 01:52 PM   #4
Old Salt
 
smoothy8500's Avatar
 
Join Date: Oct 2009
Location: San Clemente, California
Posts: 1,535
I read somewhere the M855A1 acceptable accuracy was 5.5MOA. Perhaps that is why rifles firing those rounds only will have the new wear guidelines?

smoothy8500 is offline  
Old March 7th, 2017, 02:10 PM   #5
Old Salt
 
bfoosh006's Avatar
 
Join Date: Jun 2007
Location: NW
Posts: 1,316
Sorry if I came off sounding harsh... I just can't image that a barrel that would accept an extra 2.3" of throat erosion... wouldn't be dang near a smooth bore by that point !

Hence the request for a linked source.

bfoosh006 is offline  
Old March 7th, 2017, 02:39 PM   #6
Old Salt
 
lysander's Avatar
 
Join Date: Apr 2015
Location: North Carolina
Posts: 1,761
That's not how a throat gauge works....

The gauge has a ever so slight taper on the end, so the further it goes in the larger the hole. How far and what size hole depends on the taper.

2-1/4 inches may only be another thousandths of an inch or so.

Thanks from bfoosh006
lysander is online now  
Old March 7th, 2017, 02:57 PM   #7
Lifer
 
Join Date: Oct 2006
Location: Chesterfield, VA
Posts: 3,767
Quote:
Originally Posted by smoothy8500 View Post
I read somewhere the M855A1 acceptable accuracy was 5.5MOA. Perhaps that is why rifles firing those rounds only will have the new wear guidelines?
If that's true (not saying it isn't) I wonder why anyone needs a high dollar optic to shoot a couple hundred yards? I guess some rifles would shoot better than others though. That's really sad. 5.5 MOA?? Dang. I guess you could still hit the barn door with that though.

M1A's r BEST is online now  
Old March 7th, 2017, 03:20 PM   #8
Master Gunner
 
ArmyPilot's Avatar
 
Join Date: Apr 2012
Location: El Paso TX
Posts: 887
After 26 years in the Army I can tell you that they still issue smooth bores. Most of the M16A1s I carried were lucky to hit a barn if you were standing inside of it. The A2s were great when new, same with the M4 and M4A1.
Follow the money, new ammo (M855A1), new rifles, new barrels.

Here's a nice primer on the M855A1 from G&A back in 2012.
http://www.gunsandammo.com/uncategor...s-and-marines/
Trust me, it's a good read.

Thanks from DukeConnor
ArmyPilot is offline  
Old March 7th, 2017, 07:04 PM   #9
Old Salt
 
lysander's Avatar
 
Join Date: Apr 2015
Location: North Carolina
Posts: 1,761
Quote:
Originally Posted by smoothy8500 View Post
I read somewhere the M855A1 acceptable accuracy was 5.5MOA. Perhaps that is why rifles firing those rounds only will have the new wear guidelines?
5.6 inches at 100 yards is the new rifle accuracy requirement.

7 inches is the maximum spread after a minimum of 7000 rounds.

Thanks from ArmyPilot
lysander is online now  
Old March 7th, 2017, 07:51 PM   #10
Old Salt
 
lysander's Avatar
 
Join Date: Apr 2015
Location: North Carolina
Posts: 1,761
The accuracy requirements for M855A1 is not 5.5 MOA. The actual requirements are:

Quote:
Both average vertical standard deviation and the average horizontal standard deviation shall either not exceed 6.8 inches at 600 yards or 1.8 inches at 200 yards.

While some groups may have an extreme spread of up to 5.5 inches, that is not the same as an accuracy requirement of 5.5 MOA. The accuracy requirements for M855A1 are similar to those of M193 Ball, with a requirement of:

Quote:
The average of the mean radii of all targets of the sample cartridges, fired at 200 yards, shall be not greater than 2.0 inches.
Mk 318 and Mk 262 have dispersion requirements similar to those of M118 Match and M118 Special Ball, this makes a comparison of a GP Ball round to what is essentially a sniper round highly unfair, and possibly misleading.

Thanks from rickgman

Last edited by lysander; March 7th, 2017 at 08:32 PM. Reason: The original post had some large errors in it. It needed to be rewritten.
lysander is online now  
Old March 7th, 2017, 08:28 PM   #11
Master Gunner
 
ArmyPilot's Avatar
 
Join Date: Apr 2012
Location: El Paso TX
Posts: 887
Here's another from American Rifleman.
https://www.americanrifleman.org/art...all-cartridge/
Interesting note on the "demonstrated" accuracy was done with 1 in 8 barrels, not the standard 1 in 7 issue barrels "Thus, the demonstration proved nothing". Also the locking lugs cracking "on average at 6,000 rounds, but with as few as 3,000 rounds". Not good news unless you have a armorer truck following you around in combat
Something isn't right
The M855A1 was a PC headline that war was now "green". They addressed one make believe problem and created a bunch of real ones that they have to pay for now.

ArmyPilot is offline  
Old March 7th, 2017, 08:37 PM   #12
Old Salt
 
lysander's Avatar
 
Join Date: Apr 2015
Location: North Carolina
Posts: 1,761
Quote:
Originally Posted by ArmyPilot View Post
Here's another from American Rifleman.
https://www.americanrifleman.org/art...all-cartridge/
Interesting note on the "demonstrated" accuracy was done with 1 in 8 barrels, not the standard 1 in 7 issue barrels "Thus, the demonstration proved nothing". Also the locking lugs cracking "on average at 6,000 rounds, but with as few as 3,000 rounds". Not good news unless you have a armorer truck following you around in combat
Something isn't right
The M855A1 was a PC headline that war was now "green". They addressed one make believe problem and created a bunch of real ones that they have to pay for now.
Lug cracking started occurring in serious numbers in 1999, and mainly in M4 Carbines long before M855A1 was even a thought.

The rifling twist had little to do with the "demonstrated accuracy", the rifles were match modified rifles, not just standard M4s with slower twist rifling....

lysander is online now  
Old March 7th, 2017, 10:24 PM   #13
Old Salt
 
smoothy8500's Avatar
 
Join Date: Oct 2009
Location: San Clemente, California
Posts: 1,535
Quote:
Originally Posted by lysander View Post
The accuracy requirements for M855A1 is not 5.5 MOA.


Thanks for clearing that up. I thought those numbers were too big.

smoothy8500 is offline  
Old March 8th, 2017, 12:54 AM   #14
Grunt
 
Red Leg's Avatar
 
Join Date: Nov 2016
Location: Sumner Wa.
Posts: 96
I hate to be a Debbie Downer, but nobody has stated the obvious here. With a 5.5 MOA it will cost soldiers there lives. Every enemy combatant that is shot at and missed he is still in the fight. You better believe I will be firing a letter of to my Congressman tomorrow with my concerns.

Thanks from Wasted ammo
Red Leg is offline  
Old March 8th, 2017, 01:49 AM   #15
Old Salt
 
nicholst55's Avatar
 
Join Date: Nov 2004
Location: Daegu, Korea
Posts: 1,703
Quote:
Originally Posted by bfoosh006 View Post
Hence the request for a linked source.
This came out in a Maintenace Message from TACOM (Tank Automotive Armament Command) this week, complete with graphics. If you don't have a Common Access Card, you can't access the website. If I can remember until tomorrow, I'll PM you some info.

Edited to Add: No, I won't PM it to you, as it's marked For Official Use Only. I'm too old to have to hide out in Russia like Edward Snowden.


Last edited by nicholst55; March 8th, 2017 at 02:06 AM.
nicholst55 is offline  
Reply

  M14 Forum > Rifle Forum > M16 AR15


Search tags for this page

m855a1 modified reduce wear

Click on a term to search for related topics.

Moderator Tools
Display Modes


Similar M14 Forum Discussions
Thread Thread Starter Forum Replies Last Post
9115 M1a Super Match question classicshooter The M14 2 April 10th, 2016 11:59 AM
My Problem of Barrel Protrusion Jersey Devil The M14 94 May 25th, 2013 02:24 PM
Announcing: The Wolfe Modified Medium Weight Barrel "WMMW" Hawk The M14 22 November 27th, 2010 06:31 AM



Top Gun Sites Top Sites List