I cleaned my barrel after every duck hunting weekend, and sprayed cleaner in the receiver then lightly oiled for the season. I went to do a dissembly to clean the gas cycling mechanism over the weekend, and I could not pull the barrel forward and free it from the receiver. The gas piston and sleeve move perfectly well. The gas ejection area was pretty dirty (a whole season's worth of fouling, but it always cycled perfectly) and there was a small amount of rust on the threaded 'cup' that holds it together and the thread at the end of the magazine tube (that holds the 12 gauge shells). Thinking there might be a small amount of rust holding everything tight, I sprayed some penetrating oil into the metal cylinder on the bottom of the barrel, between it and where the gas pistol slides, as well as into the receiver from the outside of the barrel. A few hours later, it's still not moving. I decided to put it back in the safe, and come back at the project. My next idea is to get somebody else to hold the stock firmly while I pull on the barrel (it's obviously unloaded) to try to free it up, that will be more force than I can apply trying to pull it apart myself. If that does not work, what next before I take it to a gunsmith? Browning Gold Hunter, 12 gauge, 3" with camo finish.