The feed ramps on the Bootleg AR 15 upper receiver are cut so that either 45 degree barrel extensions or 52 degree barrel extensions will work. All Primary Weapons Systems (PWS) rifles use 52 degree barrel extensions, but many other manufacturers use 45 degree Bootleg, Inc.’s AR 15 assembled upper receivers are designed to work with either angle. If you have further questions about whether your M4 style feed ramp will sit correctly with our assembled upper receiver, please give us a call!
