It came on a gun that I bought, and I never shot with it on, but the pins are pretty tight fitting in the frame to the point where they had to be tapped out to remove.
The mount clamps around the frame when everything is tightened (the button head cap screw goes into the large pin, and tightens from one side, and the smaller threaded pin/screw tightens from the other), so there really isn't any vector for movement unless you don't tighten something properly (it can't move back or forth because of the pins, and it can't rotate because of the clamping action), the pins have set screws to secure them in place as well.
You'd have more shot-to-shot variation that would be induced in the play between the muzzle and the front of the slide and in the lock-up of the gun than would ever be induced by this mount.
Last edited by Skeet_Man; 02/01/19.