Here's a simple test, try shimming the barrel hook with a small strip of 20lb printer paper. If the barrel hook moves appreciably to the right, I'd suspect that you need to build up your barrel hook or spindle or both. At any rate, it's a simple test, it won't hurt your gun and it could tell you a lot.
Steve

Approach life like you do a yellow light - RUN IT! (Gail T.)