Hi everybody. New to the forums and came here for some help. About a year ago I wanted to get into airsoft. Therefore, I bought myself a M59 sniper rifle by BBTac. I got this from Amazon (stupid, I know). I wanted to upgrade it, and I didn't have a proper site to buy upgrades so I went back to Amazon. I then bought the Well L96 Upgrade Set for MB01 by BBTac and the Well MB01 Metal gearbox. I don't believe that these parts were made for my gun, but when I got them, they worked. Everything was going fine for a few months until a few days ago my gun's bolt wouldn't go forward, and now, I don't know what I did but, it's slam-firing. I have no clue what's wrong with it, and I have taken it apart and examined it. Nothing seems out of the ordinary. I just want some help if anyone has an idea.