I’ve heard the Williams unit weighs 3-4oz but have never used it so don’t take my word on that!
Butch, I had a 300 RUM built up several years back. I made it heavy for using on the range and for flat country hunts. IIRC it weighed about 10 pounds with the big NF scope. It was very tolerable in that guise, even when launching 230gr Bergers at 3000 FPS. When I replaced that scope and lost over a pound it still was easily shootable. It’s definitely a fast and hard kicker but it’s also an awesome hunting cartridge for elk and other large game.