Covers threads used for Keltec factory forend installation. If using our forend these threads are exposed and unused. This part covers them and also shortens the muzzle thread length to around .625 (standard AR15 threaded muzzle length) from .750. Also allows easy timing of the muzzle device because the cover is the stop and can be adjusted by turning.
Installation instructions: Thread the cover on all the way till the it bottoms out on the ID shoulder. Install your muzzle device till it bottoms out on the cover. If muzzle device orientation is not correct unscrew it till it is then unscrew cover till it contacts muzzle device. Then tighten the muzzle device.
