The Probert Encyclopaedia of Warfare

COMPENSATOR

In firearms, a compensator is a device which is attached to the muzzle of automatic weapons to reduce the tendency of such weapons to rise at the muzzle when being fired in full automatic mode. The compensator directs some of the muzzle blast upwards, thereby forcing the muzzle down and compensating for some of the upward tendency of the weapon.
Research Compensator