You might try to pull it out?? You see I remember that little rifle and I believe there is a round opening at the rear of the receiver cut out, you know the one the bolt pin (charging handle) rides in. What I can't remember is if thatround cut outwas there only for disassembly or if it indeed was also used to make room for the bolt pin (charging handle) to either be pushed in or pulled out in order to keep it (the bolt) from closing. If I had that rifle in my hands I'd be able to tell you in a heartbeat. Fiddle with it, that's the only way to find out. Make sure it's unloaded then see if the pin will move at all once the bolt is pulled all the the way open. I'm sure there's a way to keep the bolt open.

Let me do some research into this......