Heavy-duty blocks enable the secure clamping of AR-15/M16 receiver halves in a vise, eliminating the risk of crushing, twisting or distorting them during vise pressure application or barrel nut torqueing. These blocks ensure the rifle remains stable for safe and efficient cleaning, assembly and repair. Constructed from high-pressure, solvent-resistant structural Rynite, the block and insert fully enclose the upper receiver, providing internal and external support to facilitate easy rebarreling of the AR-15/M16 by a single individual. They allow for the firm securing of a mil-spec carry handle receiver or mil-spec flattop receiver in a large bench vise for barrel removal or installation. The torque generated during barrel nut tightening is absorbed by the block and insert, rather than the receiver, thereby minimizing the risk of damage to the barrel detent pin and receiver detent notch. The blocks hold securely without marring the finish.

• High-precision injection-molded thermoplastic polymer composite material
• Compatible with A1, A2 and standard flattop receivers
• The torque has been rigorously validated to a specification of 200 ft-lb, ensuring compliance with industry standards and optimal performance under operational conditions
• Block dimensions is 2-1/2 inches length, 3-1/2 inches width, 4-1/2 inches height
• Insert dimension is 8 inches length x 1 inches diameter