Key Point: Who has a better bullet?
In Mark Bowden’s book, Black Hawk Down, he describes an incident where a soldier’s CAR-15 5.56mm carbine failed to put down an enemy combatant despite multiple hits to center mass. The ammunition used by the soldier was the M855 “green-tip” projectile, adopted by the U.S. Army and Marines in the 1980s.
Further reports of M855 underperforming lead the U.S. military on a hunt for a new cartridge that would be more effective. Surprisingly, the Army and Marines diverged in their approach, and for nearly half a decade both services fielded different cartridges as standard issue to their troops until Congress forced the Marines to use the Army round.
But which round is better? Have other NATO countries kept up with these innovations and developed “third-generation” 5.56 rounds of their own? Why did the Marines resist the change for so long?
To understand the problems with the M855, it’s worth looking at the round it replaced, the M193. The M193 was the cartridge the original M16 was designed for. It uses a fifty-five grain lead projectile with a copper jacket. It is designed to be stabilized by the 1:12 twist and twenty inches of the M16’s original barrel. The primary wounding mechanism of this projectile is yawing and fragmenting upon impact with flesh, both of which create a larger wound cavity than simply passing through.
The M193 was also adopted by a variety of other nations. Almost every nation that used the original M16 or M16A1, from the Republic of Korea to the United Kingdom utilized M193. France also adopted a 5.56mm round similar to the M193 in 1979, which also used a fifty-five grain projectile in a 1:12 twist barrel. However, due to the violent nature of the French rifles’ actions, the French cartridge utilized a steel case instead of brass.
But the M193 was not a NATO standard. In 1970, noting that the United States had diverged from the earlier 7.62x51mm standard cartridge, NATO wanted to re-standardize a single type of small arms ammunition and conducted their own series of tests from 1973 to 1979 with a variety of smaller “intermediate” cartridges in the same power range as the M193.
The trials involved firing at steel helmets at extended range, which caused rounds to be optimized for long-range ballistics and penetration on steel rather than terminal ballistics on soft targets.