The reason the M7 Grenade Launcher was used was because it has a longer range that if someone threw a grenade by hand. The M7 was preceded by the M1 and the M2 Grenade Launchers which were for the M1903 Springfield and the M1917 Enfield rifles. To fire the grenade from the M7 launcher, the rifle had to have a special .30-06 blank cartridge. Injury could sometimes occur if the user doesn't put the butt stock of the rifle against the ground.