AR10 80% Jig

thingiverse

This is a jig for completing an 80% AR-10 lower (DPMS gen 1.) This was built using the measurements on several CAD drawings found online as well as my own lower to work off of. It is made up of two halves (frame and frame mirror) with some snap in spacers to fit snug against the mag well and trigger group housing. It has additional material around the hammer/trigger and selector switch holes to help insure accurate drilling. Various drilling and milling guides snap on top of the frame halves. These guides come in two versions - short and tall. The short guides are for when you're using a drill press or mill to remove the material. The tall guides are for when you're using a hand drill and hand router. The extra height is to insure the holes are drilled straight and to make sure the hand router clears the buffer tube assembly. If the top guides can not snap onto the frames, then a slight amount of material probably needs to be removed or added to the trigger group or magwell spacers. This can be done by sanding them slightly or adjusting the z-height (make sure you don't change the X or Y dimensions!) I'm not going to include instructions on how to do the actual drilling and milling as there are plenty of guides to be found on the Internet. This is a work in progress since I've only compared the print with a single lower. Edit 1: Adjusted the trigger shoe hole size/position