Use this lapping tool to square the upper receiver face of an AR-10 or AR-15. This will improve the mating between the barrel and receiver & needs to be used with lapping compound. The pilot will also fit into the bolt carrier tunnel to keep perfect alignment throughout the receiver for improved accuracy. Includes 10ml 120 grit lapping compound.

Please specify AR 15, AR10, AERO M4E1, or AERO M5E1 when ordering.