922r applies to sbr's. Lots of good info here. Try the search, but essentially you will need to replace 7 parts with us made. Commonly, trigger, hammer, sear, cocking handle, muzzle device, stock, grip or handguard. I looked at the z43, but with all the replacement part $....I hade pcs build me a 33k. Then you are starting with a us barrel and receiver. Keep in mind the promag count as 3 922r parts, but I have not heard how they do in the mke guns.