Wilson Combat Compact Bull Barrel Reverse Plug Stainless. The Plug is installed with the hammer-end against the frame and then a hex head screw is turned on compressing the spring and preventing it from sliding back into the slide (on compact models this is a function of the hammer being pushed forward). Once the hammer-blow is complete the open end of the plug is rounded off with a knurled lip to prevent the fingers from cutting into the pistol during the initial blow-back; the knurling is molded into an S shape; the grooves are precisely machined out of the frame; the radiused ends are chamfered to prevent sliding back into the frame during use; a small milled groove is ground around the outside of the plug again preventing roll-out of the plug (an all too common problem with compact models) resulting in better lock up of the bailed round head after drawn (compact models use a separate componed trigger arm).;. Specifications for Wilson Combat Compact Bull Barrel Reverse Plug: Manufacturer: Wilson Combat Color: Silver Package Contents: Wilson Combat Reverse Plug Compact Supported for Bull Open End Wilson Combat 706: Compact Bull Barrel Reverse Plug Stainless