Just finished my 2 Polish builds, a Tantal and underfolder. these were premium kits from Akron Armory. they went together easy although the bbl pins were a real bear to get out, had to drill one of them. They worked right from the first round. test fired all of them sunday. They are parkerized black with shooters solution park chemicals and pre black with caswell plating black oxide solution.
The G3 still needs to be parked, I am getting a bigger tank to do it in. this was my first G3 and it was a real easy build. About 2.5 hours total, it shoots great, ran about 300 rounds through it so far.