My 22A shoots 6 inches high at 20 yards, cannot lower back sight any lower. Tried all the different make ammo. Any ideas?

A taller front sight or a shorter rear sight would fix it.I would email S&W and see what they say.

I bought a new 22a a few months ago. It shot high like yours. Didn't have enough adjustment to correct. Also magazine disconnected every 2-3 shots. It was one day out of the box. Sent it to S&W. When returned all was well.