Shown (from left to right) are the 30 Remington (a rimless 30-30), the new 6.8mm
Remington SPC and 5.56mm used in the M-16. The 6.8mm SPC is under serious
consideration as the cartridge for the new army assault rifle, the
M-8.
The U.S. Army is pretty serious about adopting a new caliber bullet for its infantry
weapons. Now is the time to do it, as a new infantry rifle, the XM-8, is moving
quickly through field testing. The proposed new caliber is 6.8mm (also known as
.270). Officially, it's the 6.8mm Remington SPC (Special Purpose Cartridge)
Special Forces troops were the first to use 6.8mm ammo in combat, and they were
impressed with it's better (than 5.56mm bullets) ability to take down enemy
troops. This should be no surprise, as the 6.8mm round is based on the 19th
century 30-30 round. The 6.8mm round is a modified 30-30 caliber round based on
the Remington 30 cartridge (first introduced in 1906). The 30-30 is a rimless
round first designed for lever action rifles. Most of those lever action rifles
you see in cowboy movies are 30-30s. The 30-30 round is still popular with deer
hunters because of its ability to bring down deer (of up to about 400 pounds) or
wild pigs (up to 300 pounds) at common hunting ranges (100-150 meters) without
producing a lot of recoil, or requiring a heavy rifle. The 6.8mm round has a
bullet that's about 40 percent lighter than 30-30 rounds, but about twice as
heavy as the current 5.56mm bullet. The superior hitting power can be seen in
comparing muzzle energy (1158 foot pounds for the 5.56mm bullet versus 1793 for
the 6.8mm round.) At 500 meters it's 338 versus 600 foot pounds. This means
that, out to about 600 meters, the 6.8mm round has about the same impact as the
heavier 7.62mm round used in sniper rifles and medium machine-guns.
The
30-30 was never seriously considered for military use, because when standards
for modern military rifles were established a century ago, there was an emphasis
on killing power and accuracy at long ranges (500-1000+ meters.) The 30-30 was
meant for short range shooting, not more than 200-300 meters. But what no one
really noticed over the next century was that most infantrymen used their rifles
on targets 100-200 meters away. Actually, during the 1930s, the Germans studied
their World War I experience and concluded a less powerful and lighter rifle
round would be more effective. They were working on a smaller 7mm round, but
settled on a shortened regular rifle round (7.92mm), because war was looming.
During that war, the Germans developed the first modern assault rifle, the
SG-44. This weapon looked a lot like the AK-47, and that was no accident. The
SG-44, like the AK-47, used a shortened, 7.92mm, rifle cartridge. This gave the
infantryman an automatic weapon that could still fire fairly accurate shots at
targets 100-200 meters away. The SG-44, and the AK-47, had about the same
stopping power as the 30-30. What a coincidence. The AK-47 didn't have the
accuracy of higher powered bullets, but the Russians didn't see this as a
problem, because most troops using it had little marksmanship training. If they
had to kill someone, they could fire at full auto. The U.S. M-16, and its high
speed 5.56mm round, was more accurate than the AK-47 when firing individual
shots at shorter ranges. But the wounding power of the 5.56mm (.22 caliber)
bullet fell off rapidly at ranges over a hundred meters.
The U.S. Army
has, since the 1980s, developed an army of marksmen, at least in the infantry.
Even journalists noticed this in Afghanistan, where at night they could tell
where the American troops were. The American infantry fired single shots, while
the Afghans fired bursts of automatic fire. American soldiers get a lot more out
of their weapons with well placed single shots. Better sights (a variety of
electronic and laser aided devices), plus lots of marksmanship training, have
produced infantry units that are a lot more lethal, and a lot less likely to run
out of ammo. This is not a unique development. Before World War I, the British
army, an all volunteer force, trained hard to develop good shooting skills.
British riflemen could deliver a dozen well aimed shots a minute, and keep doing
it for minutes on end. German troops who came up against this thought the
British had a lot of machine-guns (which the Brits did not) because of the
number of German troops who were going down with bullet wounds. The British were
using the .303 caliber rifle (similar to the 7.62mm by American snipers today)
and were taking down German troops at ranges in excess of 500 meters. U.S.
troops today can do the same thing, if they have a weapon with the accuracy and
hitting power to support that kind of shooting. The 6.8mm round, having a higher
velocity than the 30-30, but also a heavier bullet than the M-16, provides the
combination of long range accuracy and hitting power that American troops of
today can take advantage of. In Afghanistan and Iraq, there were many situations
where U.S. troops were able to spot enemy fighters at longer ranges (over 500
meters), but were not able to do much damage with their 5.56mm rifles. But
Special Forces troops using M-16s modified to handle the new 6.8mm ammo, got
much better results at these long ranges.
American troops in support
units are not as accurate when using their rifles, but the new electronic sights
help, and the new XM-8 rifles will still allow automatic fire, which always
helps in an emergency. The low recoil of the 6.8mm round makes it easier to fire
on full automatic. This was a big selling point with the 5.56mm round and the
M-16. The older M-14, firing full power 7.62 rounds, had too much recoil for
accurate automatic fire.
The 6.8mm ammunition is heavier, meaning about
20 percent fewer rounds are carried (unless you want to carry more weight, which
no grunt wants to do). But with troops capable to accurate single round
shooting, you don't need lots of ammo.
