Can you look through them & compare ie all in one location or different sellers. Out of that list if you could compare them you would quickly draw up...
I've found out that the barrels screw in, so it should be easy enough to remove the old one (famous last words), machine the new barrel and screw in...
About the same here. Most of my scopes are fixed 4x. The few zoom ones I have I tend to set on 6x for longer range duties (like at The Bash) or wound...