Deluxe 8 Piece PCC short stroke bumper kit. Install one of these bumpers in your buffer tube, behind your recoil spring, to “short stroke” your pistol calibre carbine.

This “Deluxe” kit includes 8 bumpers to fine tune your setup:
.2″
.25″
.3″
.4″
.5″
.6″
.75″
1″