WOW...sounds like deja vu. Gas tube didn't fit and also was canted, so I heated it a little and straightened it up, but still couldn't seem to get it to move forward. Air also goes through mine, so I am hoping it is ok. I will not pin it till I shoot it. I had to fit the gas tube by bumping the sight base back and a little fitting of the tube itself. Of course the top cover wouldn't fit then....too tight. Carrier moves, but can use a little tweeking to get it to move smoother. I ordered a new bolt, carrier, spring and safety lever, so I can relace all the parts that I robbed from my new AK-74 kit. Headspace still seems good. Except for the fact that this gun looks so cool, I don't know if I would build another.