I am officially opening the can of worms. I prefer the Weatherby, myself. It's a classic. Besides, the greater case capacity of the RUM doesn't seem to put it much ahead of the Weatherby. Not at all with some loads. What do you guys prefer?

Between the top four or so 300 Mags, there is not enough difference to make any difference. My pick beyond doubt is the 300 WINCHESTER Mag. The ammo and rifles and brass and everything is much cheaper and easy to find. No Animal could tell the difference between the 300 Win and 300 Weatherby. By Nosler manual only show about 50-70 fps between the two. The Ultra and weatherby 300-378 will gain you another 100-150 fps. again no practicle difference. Anything a guy can't kill with the 300 Win Mag could not kill it with the others either. IMO. A true step up from the 300 Win Mag would be the 375 H&H or 378 Weatherby.

to me the only difference would be the old belted/nonbelted issue. In practice the only real difference I've found is that nonbelted brass can be reloaded a few more times. other than that take your pick. I like the 300win mag.

I throw away the brass after about about 3 rounds, anyay.

Having owned a 300 wthby and paid exorbitant prices for ammo and components. I would say 300 ultra mag.

I have had both also. I perfer the 300RUM. I don't like alot of freebore. Some is safe, but I like the choice of being able to reach the lands if I want. I don't like belts. And brass seems much cheaper.

The case capacity thing is pretty moot point for me. But for the rest, its the 300RUM all the way.

James hit the nail on the head, between all the long 30 cal mags there isnt much difference in ballistics out in the field. I have a 300 H&H, 308 Norma Mag, 300 Win Mag, 300 Wby Mag and a 30-378 Wby Imp Mag. Ballistics are simular over the spectrum.... of course you see diminishing returns on the 30-378...it just uses to much powder for what I would call little velocity gain over the others. But that's just me.
What does matter somewhat is that some my rifles shoot better and are handier to carry than others and that can be a contributing factor.

And like James said....if I have the need to throttle up I always have my 378 Wby and 416 Rigby to play with.

doubleA

Weatherby is slow! Just kidding. Of the three popular .30 mags I prefer the .300 RUM. No one can argue that it is not the fastest of the three. Does this make a difference? Only to performance junkies. I admit the .30-06 would suffice for all my big game needs but I just like using the big magnums. It is the same as tinkering with hot rods. I don't need that nitrous, I just want it.

Having had almost all of the .30 cal magnums except the Warbird,and yet I still prefer the RUM.It shoots flat and hits hard,I will take the extra 100-200 fps over the weatherby,for the price of brass and shells.

I have a .300 Weatherby,good shooter but I reload a .300 RUM for a friend and I like it better because of it's accuracy...