Sorry for the confusion I was the one suggesting moving the barrel. If I remove wood from that area you suggest it will move the hammer in the wrong direction. So I'm left with either shimming out the lock or finding a thin washer to shim out the hammer or bending the hammer. Still need to check it with a cap
I guess you don't understand what the idea behind removing some wood is so I'll try to explain.
Currently the lock should be positioned by several small surfaces inside the cavity the lock sits in. When the lock is seated on these, they all position the angle of the face of the lockplate. Let's say they position the lock plate so it is in a vertical position with respect to the stock and barrel.
If a small amount of wood is removed
ONLY from the locating surfaces that are
above the center of the lock while the surfaces below the center of the lock plate are left
unchanged and you then install the lock plate so it rests on
ALL of the surfaces, the top of the lock plate will be tilted closer to the barrel so, the whole lock plate will be tilted inward at the top and the hammer will end up moving closer to the center of the barrel.
If a small amount of wood is removed
ONLY from the locating surfaces that are
below the center of the lock while the upper surfaces are left
unchanged, the lock plate will be tilted outward at the top so the hammer will end up further out, away from the center of the barrel.
Because the hammer nose if further away from the horizontal center of the lock than the lockplate is wide, a little tilting of the lockplate inward or outward will move the hammer nose a lot more than the edges of the lock plate moves. (Think about holding a yardstick in your hand. Rotating your hand just a little bit, moves the end of the yard stick a lot.) This is why removing just a little of the supporting material will move the hammer nose sideways a lot more than just the amount of wood that is removed.