If you are using a springer, you really don't want to do that. Holding a spring gun in a vice will not allow the gun to recoil as it should, and the recoil energy transfers to the gun itself. This can break the stock, snap screws off, and send small parts flying. Heavy magnums like the Diana 48/52/54 are especially susceptible. A couple shots out of a vice and the stock will come right apart.
