Abstract: A trigger housing mounting system for a firearm includes a receiver having a mounting slot and cutouts which receive mounting tabs on the trigger housing. The trigger housing is slidable forward and rearward in the receiver between locked and unlocked positions. A spring-biased locking block is movably mounted on the trigger housing. During the mounting process, the locking block is movable between a non-blocking position and a blocking position which prevents removal of the trigger housing from the receiver. A related mounting method is disclosed.

Abstract: A firearm with tubular handguard mounting system is provided. The firearm includes receiver, a barrel having a breech threadably engaging the receiver, and a handguard. A primary barrel nut threadably engages the breech end of the barrel and is moveable into abutting contact with the receiver to form a tightened barrel to receiver connection. A secondary barrel nut threadably engages the primary barrel nut and is tightened thereto to trap an external annular barrel flange between the primary barrel nut and an annular abutment surface on the secondary barrel nut. The secondary barrel nut provides a free float tubular handguard, such as an AR-15 type handguard. Additionally, the primary barrel nut and secondary barrel nut provide a dual locking feature which resists loosening of the barrel connection.

Abstract: A trigger housing mounting system for a firearm includes a receiver having a mounting slot and cutouts which receive mounting tabs on the trigger housing. The trigger housing is slidable forward and rearward in the receiver between locked and unlocked positions. A spring-biased locking block is movably mounted on the trigger housing. During the mounting process, the locking block is movable between a non-blocking position and a blocking position which prevents removal of the trigger housing from the receiver. A related mounting method is disclosed.

Abstract: A firearm with tubular handguard mounting system is provided. The firearm includes receiver, a barrel having a breech threadably engaging the receiver, and a handguard. A primary barrel nut threadably engages the breech end of the barrel and is moveable into abutting contact with the receiver to form a tightened barrel to receiver connection. A secondary barrel nut threadably engages the primary barrel nut and is tightened thereto to trap an external annular barrel flange between the primary barrel nut and an annular abutment surface on the secondary barrel nut. The secondary barrel nut provides a means for mounting a free float tubular handguard, such as an AR-15 type handguard. Additionally, the primary barrel nut and secondary barrel nut provide a dual locking feature which resists loosening of the barrel connection.