Looking for gunsmith or experienced m1 carbine owner with appropriate tools to replace or help replace gas piston and nut. I have a 1943 Underwood with a gas piston that is really stuck. I spent about 2 days with penetrating oil and finally got it to the point where I could pull it out with needle nose pliers, but there is still a lot of resistance. I tried shooting it and it cycled 2 rounds before getting stuck again. I imagine the gas block will need to be re-tapped, and that is the part I am most concerned about. If you have the experience, armorer tool/bottoming tap, and the interest, shoot me a PM with estimated cost. Thanks for looking.