File:Rotational indexing system of YHM Cobra .45 suppressor Nielsen device.jpg

This is the rear half of a Yankee Hill Machine "Cobra .45" .45-caliber pistol suppressor. The Nielsen device (also called a muzzle booster, recoil booster, or piston) is housed inside the suppressor at the rear. In this photo, the components of the booster assembly have been removed, and the suppressor has been placed on end to demonstrate the rotational indexing system. The piston, seen at left, has two steel prongs on its forward surface. These prongs slot into two of the eight semicircular steel slots seen in the rear of the suppressor. By changing which slots are engaged by the prongs of the piston, the suppressor itself can be re-oriented in any of 8 different positions along its axis. This change can be accomplished while the suppressor is still mounted to the host weapon, by pulling the suppressor forward against spring tension until the prongs clear their slots, and then twisting the suppressor to align the prongs with a new set of slots. This allows the end user to fine-tune the weapon's point of impact, since suppressors can cause subtle alterations in the way a bullet flies. Typically the operator will select the setting which minimizes the impact shift between the unsuppressed and suppressed states of the host weapon.

I created this work entirely by myself.

June 2008

ConquerorPBN (talk)

See below.