The United States Army will soon begin distributing a weapon system introduced in 1946. The M3 Carl Gustav rocket launcher will bolster the firepower of rifle platoons, giving them a much-needed edge. Developed by Bofors (now Saab), the Carl Gustav is a lightweight, man-portable recoilless rifle. Recoilless rifles are like a cross between an artillery gun and a bazooka: While they have propellant at the base of the projectile like a rocket, the propellant doesn't burn beyond the barrel, meaning the projectile flies unpowered like a bullet or artillery shell. Unlike artillery, propellant gasses are directed backwards, counteracting the weapon's...