I have a GM drop in barrel for a T/C that I need to shim to get it to fit in my stock. The screws that hold the lug on the barrel are too short after the shims. They only have maybe two threads holding the lug on. Does anyone know where I can find some screws? I don't know the tread pitch. I need them about 3/8 in long. The hole is tapped far enough in. Thanks! Joe