2AUMK3 Universal Drilling Jig

This item is typically in stock, however, there may be a delay in shipping for finishing/assembly or waiting for parts.

The 2AUMK3 is the newest iteration of our universal pin drilling jigs. It is for 223/556 barrels and has drilling positions for all four common gas block journal sizes (0.625, 0.750, 0.875 and 0.938). It is adjustable axially to accommodate any gas system and pin location. The drill bushing is also adjustable and held with a set screw.

When set up the beam will need to be checked for square, as pictured, since the beam is a slip fit in the block.

When drilling a melonite/nitride treated gas block, it is recommended to start the hole with a long 3mm end mill (available from McMaster or MSC).

Jig includes muzzle support block, drill bushing, needed set screws and one #31 cobalt drill.