Use a C-Clamp.
Look up the instruction video for the BC Tactical scout mount, in the video the clamp method is described in detail.
just removed my rear sight on my chinese military sks the other day.
There is a pin you have to punch out before removal. You have to use a small pin punch to get it out. Push it from left side to right. Once you get it out then you can push the sight down and remove (without a clamp) but it is stubborn.



























