Re: Thinking about a Magnum Rifle
It's best to think of a magnum as a souped-up version of the standard caliber. Ballistically the magnums don't shoot all that much flatter than the standard cartridges for most hunting ranges.
For instance, a 7mm RM is just a souped up .270 win. The bullets are almost identical, and 7mm is available in heavier bullets. The 7mm can either shoot the ehavier bullet than the .270, or it can shoot the same weight bullet just a little bit flatter. The amount of drop difference at 400 yards between the wo is just a few inches, close enough for hunting.
As far as knockdown power, big bullets make big holes. Big holes make the red stuff leak out faster. If the bullet goes all the way through you get TWO holes for one shot, and the red stuff leaks out even faster. Bullets are designed to mushroom so that they act like a bigger bullet. If you start out with a bigger bullet then the mushrooming is not as critical for the terminal performance. That's my basic philosophy on guns and hunting.
The .270 win CAN be used on elk, but you have to place the bullets well, and use good bullets at the same time. For instance, a 150 grain Remington Power-Point WILL kill a cow elk at 275 yards. You have to hit it in the heart, and don't expect it to go all the way though, because it won't. Not enough remaining mass in the bullet or velocity to push it all the way through. A 7mm mag at that same range using 175 grain Nosler Partitions (a much better bullet) will push a hole diagonally through a similar cow elk at the same range without any trouble.
A .300 Win is just a souped up 30-06. At most ranges (sub 400 yards) a 30-06 using decent bullets can take anything in North America. Don't expect radically better performance from a .300 win. The .300 RUM is MUCH harder on the shoulder, amd isn't that much better than the .300 win once the bullet leaves the barrel.
I now use a .338 RUM on elk. I'm planning on up to 500 yard shots being typical for a big bull. Big bullet = big hole. It'll be a once-in-a-lifetime hunt, and I want ME to be the weak link in the hnt.
Mark in Utah