De la municion 5.45 M855 a la M855A1

June 29th, 2010U.S. Army Issues New M855A1 Ammo to Troops in Afghanistan

The U.S. Army has begun shipping its new, improved 5.56×45 cartridge, the M855A1 Enhanced Performance Round, to U.S. troops in Afghanistan. The Army will procure over 200 million rounds of the new M855A1 ammo in the next 12-15 months, and soldiers in Afghanistan will begin using M855A1 ammo in the summer of 2010. The new round replaces the current M855 cartridge used by U.S. troops since the early 1980s.
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The military sought to replace current M855 ammo because M855 has not performed adequately in the Afghan theater. Specific complaints include: 1) inability to effectively penetrate vehicle windshields; 2) poor long-range performance; and 3) failure to fragment even in short-range anti-personnel use. The Army’s Picatinny Arsenal claims that the new M855A1 has improved hard target capability, more consistent performance at all distances, improved accuracy, reduced muzzle flash, and higher velocity. M855A1 ammo is tailored for use in M4 carbines but should also give enhanced performance in M16s and M249s.
[Tienes que estar registrado y conectado para ver esa imagen]New Steel-Tip Bullet Design
The 62-grain bullet for the new M855A1 ammo is a completely new design. While it may appear to have a plastic “ballistic tip”, that’s deceiving. The new bullet created for M855A1 ammo has a bismuth-tin alloy core with a steel “stacked-cone” penetrating tip. The photo at right shows the version from last year; the final production version may be slightly different (e.g. the final version tip is a different color). Apparently the latest bullet design is a winner. During testing, M855A1 ammo performed better than current 7.62mm ball ammunition against certain types of targets. According to Lt. Col. Jeffrey K. Woods, the program’s product manager, the new M855A1 ammo is “the best general purpose 5.56mm round ever produced. A true general purpose round, the M855A1 exceeds the performance of the current M855 against the many different types of targets likely to be encountered in combat.” The chart below illustrates how M855A1 ammo performs on hard targets compared to M855.
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Over One Million Rounds Fired in Army Tests
Prior to initial production, the new M855A1 round underwent vigorous testing. Official qualification of the round consisted of a series of side-by-side tests with the current M855. Overall, the Army fired more than one million rounds to ensure the new cartridge met all expectations. The new M855A1 round is the “most thoroughly tested small caliber round ever fielded” according to Lt. Col. Woods. The new M855A1 is sometimes called “Green Ammo” because it uses a lead-free projectile. Woods said the M855A1′s bullet design shows how “greening” a previously hazardous material can also provide extremely beneficial performance improvements.

``Jason Gillis, a former Army staff sergeant, first witnessed
the M855's shortcomings in 2004 on the streets of Baghdad. He
was a squad leader with 2nd BCT, 82nd Airborne Division, on
patrol when a vehicle began speeding toward his unit. After
several warnings, `both of our M249s opened up instantly,
forming a crisscross pattern of tracer that met at the
vehicles' engine compartment and windshield. Within seconds,
riflemen and grenadiers were executing magazine changes while
the vehicle kept rolling and finally stopped 10 meters from my
lead troops,' Gillis recalled in an e-mail to Army Times. He is
now a free-lance writer who often focuses on military small-
arms issues. `Assuming the driver was most likely riddled
beyond recognition, we were all astounded to see the driver
emerge from the vehicle completely unscathed,' Gillis wrote.
`Closer inspection revealed that the M855 ammunition had failed
to effectively penetrate the vehicle's windshield despite the
fact that over 400 rounds were expended at extremely close
range and on target.' Other soldiers say they like the M855
because it is lightweight, but wish it had more punch. `The
idea of being able to carry 210 rounds [basic load] is quickly
overshadowed by the fact that it takes more than one and even
more than two rounds to drop the enemy,' Staff Sgt. Charles
Kouri, 82nd Airborne Division, told Army Times.''