Thanks, unscrewing easily definitely isn't the case with it. I'll hit it with some heat. If the head continues to strip, I'll tap the screw driver in a little and give that a go. I'm assuming they wouldn't have used a thread locker from the factory on this thing.
Don't assume anything; Nork pistol sights often have some sort of locking compound on them; they take a strong blow with a punch and hammer to get them moving. Once moving, they are not exactly easy to move, but are much easier than they were.