Back in 2005, the U.S. Armys design
for a new assault rifle, the XM8, was cancelled. But now the manufacturer has
incorporated one of the key components of the XM8 into M4 rifles, and calls the
hybrid the H&K 416. Heckler & Koch (H&K) designed the XM8, which
was based on an earlier H&K rifle, the G36. SOCOM is using the 416, but no
one else is (except for a few police departments).
The XM8 had one major advantage over the M16. The
XM8 (like the G36 and 416) uses a short-stroke piston system. The M16s uses
gas-tube system, which results in carbon being blown back into the chamber.
That leads to carbon build up, which results in jams (rounds getting stuck in
the chamber, and the weapon unable to fire.). The short-stroke system also does
not expose parts of the rifle to extremely hot gases (which wears out
components more quickly). As a result, rifles using the short-stroke system,
rather than the gas-tube, are more reliable, easier to maintain and last
H&K developed the 416, for SOCOM, at the same
time the XM8 was being evaluated by the army. SOCOM got the first 416s in 2004,
a year before the army cancelled the XM8. The 416 looks like the M4, for the
only thing that has changed is the gas system that automatically extracts the
cartridge after the bullet has been fired, and loads the next round.
In dusty places like Iraq and Afghanistan, you have
to clean your M16 and M4 rifles constantly, otherwise the combination of carbon
and dust in the chamber will cause jams. The army and marines both decided to
stick with their current weapons, rather than adopt an easier to maintain
weapon, like the XM8 or 416, because of the billion or so dollars it would cost
to switch rifles. If the issue were put
to a vote, the troops would vote for a rifle using a short-stroke system. But
the military is not a democracy, so the troops spend a lot of time cleaning
their weapons, and hoping for the best.