Hello all new to the forum and a very happy owner of the SP15 sport II, Decided to swap out the MagPul MBUS rear sight that came with the rifle with a Nikon P223 scope however I am having an issue trying to get the old rear sigh over the gun collar.
Everything else is standard on the rifle, is this just a matter of brute force which will more than likely scratch or damage the rifle collar or is there an process?

Thanks in advance
Mike

Loosen nut and remove MBUS cross screw.
Pull back on the charge handle or remove it.
Slide MBUS off the rail.

Thank You worked and so easy you can tell i'm a newbie..

Thanks again
Mike