***update***

The new parts arrived today. I took the carbine down and locked the barrel into my shop vise. The piston nut refused to budge. I ended up welding the piston to the nut which is a real trick considering the wall of the nut is tiny and you don't want it welded to the receiver. Once that was done I welded a 1/4 x 20 nut to the end of the piston. A 7/16" wrench spun it off but it didn't come easy.
I stuck the bore scope down the pipe and shot some brake cleaner into the gas port. There was a slight dribble into the chamber. I pulled out a .0625" drill bit and started cleaning the port. I was pulling out all kinds of nasty stuff. I was watching through the bore scope while turning the bit. I didn't want to hit the far side of the bore with the bit. That's when I broke through into the bore. Oopsie! I now have two gas ports. I guess it's a good thing the Criterion barrel is on it's way. the two holes are about 20 degrees apart. the new port is straight. The old port is off to the side.
I went ahead and cleaned up the gas cylinder. It was ugly in there. various bore cleaners were not doing the trick. I ended up using a foaming bore gel on a low speed Dremel buffing wheel. The piston now fits in the hole but it is tight. It will not pass the tilt test. Sometimes it's hard to pull rearward with my fingers. I'll keep working with it.

So, now that the gas port is officially too large, what's going to happen? Will it slam the bolt through the back of the receiver and into my forehead?
Who wants to pull the trigger first and find out what happens?
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