Perhaps a downside of trying to make an enhanced performance round meet environmental regulations (which only matters on the training range), is that the two inevitably end up at odds with each other. Case in point, the modern M855A1 and M80A1 rounds have been prohibited – for the time being – for use in shoot houses, due to their potential to penetrate existing live fire shoot house barriers. From SoldierSystems.net:

Early this year, the US Army released guidance curtailing the use of M855A1 and M80A1 enhanced performance ammunition in live fire shoot houses until further notice due to over penetration of ballistic backer materials in the structures.

R 061517Z JAN 15
FM ALARACT RELEASE AUTHORITY WASHINGTON DC
TO ALARACT
BT
UNCLAS
SUBJ/URGENT ALARACT 004/2014 – STOP USE OF M855A1 AND M80A1 EPR AMMUNITION FOR TRAINING IN LIVE FIRE SHOOT HOUSES (LFSH) UNTIL TESTING IS COMPLETED

THIS URGENT ALARACT MESSAGE HAS BEEN TRANSMITTED BY USAITA ON BEHALF OF HQDA ASO//DACS-FS//

1. (U) BACKGROUND. THE EPR 5.56MM M855A1 AND 7.62MM M80A1 ROUNDS BOTH HAVE INCREASED VELOCITY AND IMPROVED PENETRATION CAPABLIITIES OVER CURRENT STANDARD AMMUNITION (5.56 M855 AND 7.62MM M80). THERE ARE SAFETY RELATED CONCERNS THAT THESE NEW ROUNDS MAY POSSIBLY PENETRATE THE EXISTING MATERIALS THAT ARE USED IN CONSTRUCTION OF LFSH (SHOCK ABSORBENT CONCRETE, WALLS FILLED WITH PEA GRAVEL OR SAND, AND 3/8 INCH AND 1/2 INCH AR 500 STEEL).

2. (U) TESTING IS ONGOING TO IDENTIFY WHICH LFSH CONSTRUCTION MATERIALS WILL CONTAIN PROJECTILES. THE M855A1 AND M80A1 EPR AMMUNITION SHOULD NOT BE USED DURING TRAINING IN ANY LFSH UNTIL TESTING OF CONSTRUCTION MATERIALS IS COMPLETED AND ANALYZED.

3. (U) HQDA G-3/5/7 HAS AUTHORIZED THE FOLLOWING AMMUNITION FOR USE IN LFSH: LIVE BALL-M855, M80; SHORT RANGE TRAINING AMMUNITION (SRTA)-5.56MM M1037 BALL, M862 PLASTIC AND 7.62MM M973/M974 LINKED 4
BALL/1 TRACER; AND CLOSE COMBAT MISSION CAPABILITY KIT (CCMCK) FORCE-ON-FORCE LOW VELOCITY MARKING AMMUNITION.

4. (U) POC: Redacted by me.

5. (U) EXPIRATION DATE IS 22 APRIL 2015.

While the Army now has some additional work to do creating new LFSH barriers that can reliably stop the two new rounds, at the very least this development should help assuage concerns that the rounds don’t represent a meaningful improvement in performance over the older standards!