Bolt Together AR AK grip adapter.

thingiverse

The final piece of the puzzle to complete that AR-15 7.62x39 build with a Bolt lower is within reach. So, you've got a PSA side charging upper and a lower without a bolt release, paired with an utterly wild RIS system. Essentially, you've transformed an AR into an AK, but now you want to ditch the A2 grip? This adapter is your solution. This ingenious adapter replaces the grip tang on a bolt-action AR-15 lower receiver, allowing for the installation of an AK-style grip instead. The only deviation from standard installation is that the safety detent spring needs to be shortened or replaced, as the AK grip doesn't provide space for the other end. Since it can't utilize an AK's grip screw or receiver tang, new hardware is required. I designed a 1/4-3 inch machine screw extension and nut available at Harbor Freight, but any 3-inch long bolt will suffice, and there's also clearance behind it to accommodate a 3 1/2 inch long bolt. Simply glue the nut in place or shim it to prevent rotation, or you might never get it back off.