No U.S. military service rifle caliber has been more controversial than the 5.56x45mm cartridge which was adopted in the 1960’s along with the M16 rifle. Somewhere along the line both Soldiers and civilians began to perpetuated the myth that the 5.56 round was designed to wound the enemy and not kill them. The logic behind this claim is that wounding the enemy puts a strain on their logistical systems with the added bonus that it requires other enemy soldiers to carry their wounded brethren from the field of battle thus lessening the number of combatants to contend with.
The only problem with this myth is that it is just that, a myth.
The U.S. military has never published any documents, requirements or doctrines stating a desire to adopt a rifle cartridge designed to only wound the enemy. The 5.56mm cartridge was designed from the beginning to kill enemies, not to wound or maim them. Ironically, when the M16 was first fielded many Soliders were amazed by the nasty wounds it inflicted.
When the M16 was first adopted, the rifle used a 20″ barrel with a 1:14 twist. The slow twist rate of the barrel meant the 55gr bullet of the 5.56mm cartridge was under stabilized. This, coupled with the thin jacket of the bullet fired at high velocity, contributed to the horrific wounds. The Russians thought the wounding characteristics of the M16 in Vietnam were intentional which influenced the development of their 5.45×39 cartridge for the AK74. Due to the wounds produced by the AK74’s 5.45×39 cartridge, it became known as the “poison bullet” in places like Afghanistan.
The instability of the bullet when fired out of the original 1:14 barrels of the early M16’s was not intended as it reduced accuracy and the effective range of the rifle. Fairly quickly the U.S. Military moved to increase stability of the projectile by going to 1:12 twist rate, which spun the bullet faster thus increasing stability. Later, in the 1980’s, the M16A2 would adopt a 1:7 twist rate which is now used in the modern M16A4 and M4 carbines. Many felt that 1:7 twist rate over stabilized the bullet which in turn caused it to zip right through bad guys causing minimal damage. The myth the 5.56mm was designed to wound and not kill gained traction.
Countless horror stories told by Soldiers about the 5.56mm’s failure to neutralize a target emerged from the wars in Iraq and Afghanistan which prompted the U.S. Military to investigate the claims the cartridge was ineffective. In 2003 the U.S. Army conducted a study that found the 5.56mm was actually a capable combat cartridge. This quote from the study carries a lot of weight in my opinion.
In the end, “footpounds of energy” is misleading, “stopping power” is a myth, and the “oneshot drop” is a rare possibility dependent more on the statistics of hit placement than weapon and ammunition selection. Effectiveness ultimately equates to the potential of the weapons system to eliminate its target as a militarily relevant threat.
I agree with this statement. Shot placement will be the largest deciding factor in how effective a gun shot wound will be in terms of dispatching the enemy. The horror stories about the ineffectiveness of the 5.56mm can be traced back to either unsubstantiated rumors and myths or to poor shot placement.
It’s also worth noting how the 5.56mm stacked up against the .308 in the testing. For close quarters type combat the 5.56mm kept pace with the 7.62×51(.308) in terms of effectiveness which bucks conventional wisdom that states anything .30 caliber will trump anything .22 caliber.
It’s also interesting to note that when the U.S. military adopted the .308 to replace the 30-06, similar horror stories circulated. The .308 was deemed to be inferior to the 30-06 by many Soliders. Slowly these rumors faded with their demise being hastened by the adoption of the 5.56x45mm only a few short years later.
The 5.56mm cartridge is a fine service rifle cartridge that excels at close to medium range combat. It is not well suited to long distance engagements which is why the U.S. military has moved back to the .308 for DMR’s (Designated Marksman Rifle) in the wide open spaces of the Middle East. However, for a general purpose combat rifle or survival rifle you would be hard pressed to find a more suitable caliber than the 5.56x45mm under most circumstances.