At 25 yards I am shooting 4” right. My rear sight is marked L. Can I just buy an unmarked rear sight to correct? I tried drifting front sight a little but it won’t budge.
An unmarked rear sight (which does not have an offset notch) is the best solution. Pushing the front sight leaves it perched off on one side, and is neither aesthetically nor functionally desirable.Finding a person or gunsmith with a universal sight pusher might be a solution, or carefully mounting the barrel into a vise with hardwood or brass braces to secure the barrel before drifting the front sight in the opposite direction of your desired bullet impact. It will move; you just have to be careful, and more determined than the front sight.
Half a millimeter is about 1/50th of an inch.A mere half a millimeter on a 3” sight radius produces a sighting error of almost 3” at 25 yards, while a Thompson/Contender with nearly a 15” sight radius is only off about 6/10th of a inch at the same range.