AR gas block Dimple Jig

thingiverse

Gas block dimple jig for an AR. comes in .625 and .750 sizes.one of your gas block set screw locations is always directly opposite the gas port. This jig is slipped over the barrel and has a hole that lines up with the gas port to make a dimple in the correct spot.Hardware needed:1/4-20 tap1/4-20 cone point set screw5/16 OD bushing (ID depends on your transfer punch/drill size, I used 1/4)Assembly:on one side the hole is the tapping size for 1/4-20, tap this hole as straight as you can and install a pointed screw to locate against the gas port.the opposing side of the hole is 5/16, either use an appropriately sized transfer punch through this hole or push in a 5/16 OD bushing for better accuracy.directions for use:this jig should be a (close) slip fit, sand main bore if needed. slide jig onto barrel, align screw side with gas port and slowly tighten, you should feel the jig self-align as the tapered screw falls into the gas port. on the other side of the jig, mark location with a transfer punch and/or drill through bushing. when drilling, use plenty of oil, and check progress, don't go too deep. It's a dimple, not a hole. If using a bronze bushing like I did, consider it a one-time-use.