I am thinking of building a similar AR to the DDM4 V7, but with piston instead of direct impingement. I have seen kits that will change the operation of the AR to piston from gas but if not for the kit, then what parts I needed to do this? I plan to start with a DD stripped lower (if I can find one), likely a Geissele trigger, etc.
-also-
What would be your best choice for a stripped lower (in the very possible case I don't find a DD)? There are so many to choose from.
-also-
What would be your best choice for a stripped lower (in the very possible case I don't find a DD)? There are so many to choose from.


















































