Guess I've been extremely lucky then, but more likely, careful with my customers property. I've had a federally licensed gun repair business, with a full fledged machine shop, since 1971 and have worked on a countless number of Ruger Mark pistols. My bench will employ rolled leather mallets, too light for getting seriously tight Ruger Mark pistols apart, mallets with phenolic resin and nylon faces and heads, hard nylon and even a plastic hammer with lead shot molded inside the heads. Called a dead blow hammer. Never, in 43 years, have I distorted a Ruger Mark pistol receiver, or managed to injure a rear sight in any fashion by using any of the hammers/mallets I mentioned above. When using the set-up I use for holding Ruger Mark pistol grip frames (panels removed) there's no way this side of the sun, that any grip frames will ever get twisted or damaged because of the molded, grip frame accepting, false jaws, I use to hold these pistols in my bench vise. Optics, should always be removed from Ruger Mark pistol receivers before the hammer starts moving in that direction. Can't imagine working on a pistol with any optics still mounted on it, when stubborn separation is called for. :roll: Brute force is never a good idea when working on any firearm, but thinking ahead and protecting the process as best that I can, is always a much better idea for my customers, and me.