AAC’s A.S.A.P system allows the silencer to function properly with tilting barrel semi-automatic pistols. However, when used on fixed barrels hosts, the A.S.A.P system needs to be disengaged for proper function. The fixed barrel spacer replaces the driving spring to render the A.S.A.P System appropriate for use on fixed barrel hosts. The new and improved fixed barrel spacer is designed for all Ti-RANT 45 series silencers. When installed properly NO gap between the silencer body and the rear cap. Different from the prior design which purposely left a gap for visual identification.