If you are removing a sight in a ramp, make sure the ramp is supported, so the force isn't applied to the ramp/barrel joint. A sight pusher is vastly superior. You do not want to knock the ramp off the barrel.
It can be better to clamp the barrel in a padded vice than to try to clamp the stock. The closer the padded vice is to the sight the better.
If you get brass or copper smears on the gun, use bore cleaner.
There are punches with nylon tips. This has less cushionning effect that a bar of nylon.
Don't be afraid to shape the tip of the punch so that it will fit the job.