Re: 300 rum o.a.l.
You guys are right. I have the little brother 7RUM and I can't make most bullrts touch the rifleing and still be in the case neck. My mag box is a hair longer though cause I seat mine at 3.71 and still have 5 thou clearance. I think all the factory RUMs have a very long throat so not to cause excessive pressure by jamming a bullet into the riflings. I think weatherby also does or did it too on their big cals like the 300 weatherby and 30.378 and the 338.378. Dont quote me on that until someone that really knows what their talking about confirms it! Just seat them to fit the mag box is about the best you can do unless you want a single shot.
Guns and ammo, what more do we need?