u/Hopeful-Bowl6759

My dad let me take is old chinese B3 air rifle to toy around with today. I put probably 50 shots through it and then my lever suddenly got very stuck. I got it open but it felt like I was forcing something. The next time I tried to open it, it would only open about half way through. I can’t really tell what is going on with it, any ideas as to how to get it to open fully? I can’t provide more pictures if needed.