Continuing to address some defects in firearms as they come up; Myself and 2 others all agreed the rear sight on my Norinco SKS is too narrow. It's such a tight fit for the front sight that it all just goes blurry, astigmatism ya know. The only, only time it's clear is when you're in full sunlight aiming at bright-white snow background. Can I replace this rear sight, or file it out to be wider? Would painting a U like on a Glock rear help?