I recently bought a used AMT CAL.22 L.R./H.V. BACK UP and im having nothing but problems. The gun keeps jamming. It will eject the shell once in a while but not all the time the rest of the time i have to manualy open the chamber and manual remove the shell. I have searched online for a manual so i can break this gun down for cleaning hoping that will resolve this issue. Has anyone run into this problem with this gun and might know how to resolve this problem? It very hard to find ANY info on this particular gun. Any help would be appreciated. Thanks.