some how I got it in my head they were polish . likely becasue my polish hunter build.
I have a reciver sitting at a FFL I might just do a quicky screw build on in 7.62x39 as that what the ejector tip will be length wise. I can always unscrew it an sell it as a pistol kit if i dont like it or need the reciver.
I was thinking I could make a simple block to house the tube an GB front sight all in one piece. basicaly just need three holes bored into it one not clear through. I have stainless tubing that fits a piston perfect press the tube in the hole an a allen or pin to hold it an add piece on the rear to take the dust cover. should be pretty simple. maybe even make the bottem of it a integeral hand guard/ finger stop. I would not need to buy a rsb, gb or a front sigth block or a gas tube. an I could go aluminum to reduce some weight. Just thinking out loud.