Years ago I bought a 1992 Navy Arms import TU-711 Broomhandle. These were made in China and are semi-auto pseudo clones of the Mauser 712 fully automatic "Schnellfeuer" Broomhandle. The TU-711 is basically a Broomhandle that takes magazines. That's about it. Anyway, on my pistol I cannot retract the the bolt. It simply will not move. I disassembled it per instructions from ewe-tube videos. Everything inside is clean and oiled up. I can disassemble and reassemble the pistol as instructed. When disassembled, the bolt retracts with ease and all looks fine. But when reassembled, it is still frozen in place. I am not Broomhandle literate and don't know what to try. Any and all assistance would be greatly appreciated.