M100 Grenade Rifle Entry Munition
The M100 Grenade Rifle Entry Munition is a light-weight, muzzle-launched, standoff-breaching munition that can be fired from the M16 or M4 series weapons with 5.56 mm service ammunition, either M855 Ball or M856 Tracer.
It is the first-rifle launched grenade to provide door-breaching capability, which includes steel doors.
It provides the Soldier with capability to breach doors and windows from a significant standoff range.
And, it is fired from standard rifle and carbine with standard combat ammunition.
Source:
http://www.pica.army.mil/picatinnypubli ... -23-06.asp