Recoil buffer
A recoil buffer is a factory-installed or aftermarket component of firearms which serves to reduce the velocity and/or cushion the impact of recoilling parts of a firearm.
Design
The simplest form of recoil buffer is made from a resilient and deformable material (leather, rubber, polymer e.g. a rubber butt pad on a shotgun). A second way of producing a recoil buffer is to insert a spring into the recoil train—the path/part(s) generating recoil impulse. This spring is mounted to the point(s) where the firearm contacts a mechanical holder such as a tripod or human upper torso. Reducing the initial jolt, the rate and/or extent of rearward displacement, and any internal impacts in the operating parts of a firearm can reduce the shooter's perception of recoil, and may also work to extend the life of the mechanism and its parts. More sophisticated designs use hydraulic or pneumatic shock absorbers; systems of springs, cams and levers to modify, dampen, or dissipate the rearward impulse generated as the projectile is fired down the bore of the firearm. Aftermarket buffers are often moulded bumpers or additional springs placed between operating metal parts which impact one another, such as the slide and the frame of a semi-automatic pistol. This type of buffer cushions the battering force of repeated metal on metal impact, reducing wear on parts and lengthening the service life of the firearm. Reduction of perceived recoil discomfort is an immediate added benefit of this type recoil buffer.