Not saying that its bad, but how is your trigger control?
If you're hitting right, you may have a bit much finger on the trigger which is consistently pulling your muzzle to the right when you're shooting. Well, assuming you're right handed and not wrong handed.
That being said, if you have good trigger control, then you may need to drift your sight. As long as you or an acquaintance of yours has a rear sight drifter, it shouldn't be too tough.