Not gonna hurt the 4506. Fine shotguns, some rifles, and all rim fire guns shout not be dry-fired, but you ain't gonna hurt a 4506 with dry firing. I think if I kept track of the dry-firing I would be in the multiple millions of times with my handguns, covering several decades and over 100 guns. Never a tiny bit of damage done that way. Snap caps for rimfires but never with anything else.