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.
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Originally posted by Bronx: I just realized after learning all this stuff about LCT, that we are soul mates.
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Subject: barrel comes loose when i fire my gun a few times? 
