Overview Reviews Product Description BCM Low Profile Gas Block for AR15, M16, M4, M4A1. Machined of steel, phosphate finish, for .625 barrels. Manufactured within very tight Mil-Spec tolerances on all ID's. Barrel ID honed after finish per USGI TDP. Made by Bravo Company MFG, Inc. with set screw mounting. Product Videos Custom Field Product Reviews (No reviews yet) Write a Review Write a Review × BCM BCM Low Profile Gas Block (0.625") Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name *Email *Review Subject *Comments