I bought a gen 4 model 22 new 4 months ago. I fired 500 flawless rounds and cleaned it. I chambered a round and it sat. I go to unchanged and the slide feels stuck. I pull very hard and the round slowly comes free. It has rust all over it and the chamber. Could this be the Hoppes bore foam after effects? Glock said to send the barrel back. Can a serial numbered barrel be shipped without an ffl?