Stan

Had one of the early, black receiver M200E's as imported by Ithaca in the early 70's and removed the Ray-bar for the same reason. My sight was a standard, right-hand threaded one and of small diameter, possibly 3-56 if memory serves. An overnight soak in Kroil or similar penetrant and easy pressure with a small-jawed crescent wrench should not do any harm, I'd think, as that's how mine came off.

rob