Patent attributes
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.