barrel comes loose when i fire my gun a few times?

hey guys just wondering what might cause this to accure is there an o-ring that goes on the barrel?

it can happen just from the weight and force of the bolt moving back and forth from shooting, but there might be a problem with the fit of the barrel it should stay put when you tighten up your barrel. A fix might be to simply put an o-ring around the top of the threads where it meats with the gun body. It that dont work then you can try a thin layer of pipe tape.

Is it the orginal stock barrel for the gun?

yea it sure is lol its stock BUT im upgrading the gun in like a week to a 12"