This is a custom made BRDE gas block drilling jig used to drill Spikes 0.750" bore gas blocks for pinning.
Cold rolled carbon steel
Waterjet, machined and hand fit opening
Manganese Phosphate finish
#31 hardened drill insert
Includes 1/4"-28tpi x 3/8" soft point set screw
Includes one #31 jobber drill bit and one 1/8" hex key