I have used a relatively cheap Ebay sight pusher, it was like 20 bucks. Kind of a PITA to set up, but once clamped on solid it worked well, make sure to put some padding like leather or even the fuzzy part of velcro on the steel clamp blocks. It works best on the flat sided slide like Glocks, but I managed to get it to work on an M&P9 with the cut slide.