I currently shoot a Ruger M77 MKII in 300 Win Mag, it is not set up for long range shooting, it wears a Leupold Vari-X III 2.5-8x36 that I put on it for use in Alaska. I am considering buying a new rifle, and I am trying to decide whether to stick with the 300 Win or maybe move up to the Ultra Mag. I want a rifle capable of harvesting an elk or an Oryx out to 800 meters. This has been brought on by the frustration of a recent hunt for Oryx here in the New Mexico desert.
I would say stick with the win mag. The difference in performance between the two is negligible in my opinion but the difference in the amount of powder burnt burnt and felt recoil is substantially higher. If you handload the win mag looks even better. QL states a long throated 300 win mag loaded with a 240SMK (which i know isnt a hunting bullet but just using it because it weighs a ton) with a 26" barrel and 78 gr. of retumbo will have a muzzle velocity of 2780FPS and max pressure of 60,620 psi. 300 ultra with same bullet also with a long throat to keep things fair will push the 240 SMK with again a 26" barrel and 98 grains of H50BMG will have a muzzle velocity of 2821 fps and pressure of 65,396psi. Which dosent seem correct to me at all (unless i am doing something wrong here the 300 win mag seems like the clear winner.) In my opinion i think the 300 ultra is just too much case to be taken advantage of in a hunting weight rifle.
Remington 700 7mm SAUM Magnum Research Barrel
Savage Target Action 6.5x47 Lapua
Savage Predator Hunter Max1 6.5-284 Norma
Savage Bear Hunter 338 Win Mag
"Gotta Kill It Before You Can Grill It"
If you don't see yourself shooting game past 800-1000 yards the 300 Win will be great. Barrel life is better, you will burn less powder and will have less recoil. Right now, IMO probably the best long range bullet for the 30 cal rifles from 300 Win and up is the Berger 215 Hybrid. You should be able to handload it somewhere at or above 2800 fps. My 27" 300RUM launches the 215's at 3185fps. That brings me to my next point. There is a BIG difference between the 300 Win and the 300 Rum when we are talking about performance. Yes, less barrel life, more powder to burn and you will want a muzzle brake. I wanted a rifle capable of cleanly taking elk to 1200 yards, that's why I switched to the 215 recently. It just depends on what a person is trying to accomplish.
I've got the 215's coming out of my 26" 5r 300WM at 2940 fps and the 230s coming out at 2800 fps. Both of these loads are more than adequate for delivering kill shots beyond 1000 yards. If you absolutely must drive them harder you'll need to step up to the RUM.
As others have mentioned, there are considerations for the RUM with powder and barrel consumption over the smaller WM. If you need the added performance and can deal with these considerations, then by all means, get a RUM
I have been shooting a lot of the 208gr AMax bullets as I got a smoking deal on them, but I wouldn't trust them on anything larger than a deer. There are places here that are like the S. E. corner of Oregon, a guy could target shoot 2000 yards if he wanted to. The Ruger has given me some amazing accuracy, just doesn't have the glass, and not sure if the factory rings are up to the 800 yard distance. The RUM will likely be the route I choose, just because I eventually I will want more than 800. This will be a 3 to 4 year quest, in the meantime I will save for some glass that will get me to at least +800.