Re: .300 RUM kicks like a mule
Well, I have a Winchester Sporter chambered in a 358-404 Imp, basically 280g/2900fps/92g of powder, and it weighs all of 9.5# scoped and loaded. I put a deccelorator pad on it, and it ain't bad at all. I'm only 180# on a fat day, and it's much easier than load development for my dad's 375 H&H Ruger #1.
In fact, I put almost 30 rnds thru it a couple weeks ago with no ill effects, along with a bunch of FAL plinking.
So, Ezy, forgive me if this seems overly basic, but proper form is a must. I shot a hotrodded 6.5x55 from a M700 Classic, and it was freakin' stiff! Something like 140/2825, but you still had to brace up.
IF you are new to shooting heavy/fast guns, make sure to find some buds around, willing to watch you and give pointers. Otherwise,best case scenario you end up learning to tolerate it and develop some poor habits around it.
Good luck and happy shooting!