I recently acquired a Polish AKM built on a 1.6mm Armory USA receiver. I was going to put some Polish furniture on it - but of course it doesn't really fit, since the receiver is 0.6mm thicker then it's supposed. I could of course just grind down the wood, but I thought I'd check in on how difficult is it to grind down the receiver on the inside? Doesn't look that difficult, but I thought I'd check in with the community