The U.S. Army has finally addressed years of complaints about the M-4 and M-16 assault rifles. The M-4 is a short barrel M-16, and has become very popular with the troops. The army has asked the Department of Defense for permission to spend a few hundred million dollars on upgrades for its 400,000 M-4 assault rifles. The big change is replacing the main portion of the rifle with a new component that contains a short stroke piston gas system (to reduce buildup of carbon inside the rifle) and a heavier (by five ounces) barrel (which reduces barrel failure from too...