Hammer retarder

The hammer retarder (also known as rate reducer) is a component of the automatic firearm that delays the hammer fall^[1] and thus reduces the rate of the fully automatic fire.

A sketch of an AKM-like hammer retarder produced by AI

The retardation of the fall serves two purposes:

• delaying the shot until the bolt is fully locked;^[2]
• decreasing the speed of firing to improve the firing precision.^[3]

AKM

Location of rate reducer on a diagram of AKM

Use of a cyclic rate reducer is the main difference in the operation of AKM when compared to AK-47 (the latter does not have the component). The hammer retarder of AKM is located alongside the trigger and the semiautomatic sear and replaces one of the twin lugs on the trigger. The cyclic rate reducer functions by momentarily holding the hammer in the cocked position after the automatic sear has disengaged. The hammer has to overcome the inertia of the heavy rate reducer before it is released; this causes a slight delay, with a resultant decrease in the automatic rate of fire.^[4]