I'd do that only in an emergency, like no Lott ammo arriving with the rifle. Even though some say it will do no harm, I never do it. Since the 458WM is shorter than the Lott, the Lott chamber is "fire-etched" at the end of the length of the WM brass. Those same say that all you have to do is clean the chamber thoroughly and it should be OK. All you have to do to examine the Lott chamber after a few WM's and you'll see the damage to the chamber. Over time, with enough WM's through the rifle, the Lott brass will flow into the circumferential etched area and you'll have stuck brass.