Finally an easy and effective way to attach your Ti-RANT 45 to a 300AAC BLK host! Allows all Ti-RANT 45 variants to be directly threaded to a 5/8-24 barrel for use with subsonic 300 AAC Blackout ammunition ONLY. Replaces the Ti-RANT piston and driving spring to render it appropriate for use on a fixed barrel. Innovative wave spring design is used to tension the rear cap while assembled to prevent unintended loosening during use. When installed properly there will be NO gap between the silencer body and the rear cap. Conventional stand-alone fixed barrel spacer is not needed, as this part effectively combines the 5/8-24 piston and fixed barrel spacer into one part.