That said, there are real disadvantages in terms of excessive recoil and shorter barrel life that come with the cartridge. If you’re looking for a shorter, lighter, and/or handier rifle, then you probably should choose a cartridge other than .300 Ultra Mag. Interestingly enough, both companies decided to use a larger diameter, beltless case as the basis for their projects. The Big Game Hunting Blog is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to,, and other Amazon stores worldwide. This means I will earn a small commission (at no extra cost to you) if you make a purchase.

The magnum era in North America kicked off with the introduction of the 7mm Remington Magnum and .300 Winchester Magnum in the early 1960s. The .300 RUM undoubtedly deserves the “Ultra Magnum” moniker, but that incredible performance does come at a price. Since there’s so much overlap in their common bullet weights, rifles for both cartridges typically use a 1:10″ rifling twist. Thanks for your support. In fact, it ranks right up there next to the .30-378 Weatherby as the flattest shooting and hardest hitting .30 caliber cartridge in widespread use. Once again, the cartridges perform pretty much like you’d expect.

At the same time, the 300 RUM has a slightly longer case neck than the .300 Win Mag (.306″ vs .264″). These figures for the 180 grain bullet weight were later revised to 3250fps. The 300 RUM certainly offers some significant ballistic advantages to hunters.

Pistol; Rifle; Cowboy; GR. If you can deal with the recoil and want a flatter shooting and harder hitting cartridge, then the .300 Ultra Mag might make sense for you. Fortunately, availability of ammunition is usually pretty good online though and most of the bigger retailers typically have a good selection of quality factory 300 RUM ammo in stock. Those shooters are better suited to take advantage of the improved ballistics of the 300 RUM vs the 300 Win Mag.

Recoil is much more manageable and the cartridge is generally much easier on barrels. That said, the 300 RUM gives hunters the ability to wring more performance out of a .30 caliber magnum cartridge for long range shooting and hunting. This means that, in general, the 300 RUM will wear out barrels faster than the .300 Win Mag will (which can be a bit of a barrel burner itself). Basically, the 300 RUM is capable of firing the same weight, or slightly heavier bullet at a faster velocity than the .300 Win Mag. Finally, since it uses the same .308″ bullet size that’s also used by the .308 Winchester, .30-06 Springfield, .300 Win Mag, and .300 PRC (among others), reloaders have access to a good number of outstanding quality bullets in the 180-220 grain range suitable for use on a wide variety of game to choose from. If you’re looking for a load with less recoil, then maybe download that 180gr load, or do the same with one of the lighter Barnes bullets? The .300 RUM typically uses bullets in the 150-220 grain range with 150 grain, 165 grain, 180 grain, 200 grain, 210 grain, and 220 grain bullets being most common. The .300 Ultra Mag can fire the same weight bullet approximately 200-300fps faster than the .300 Win Mag. This is a classic example where the saying “a hit in the right place from a less powerful cartridge is much more effective than a hit in the wrong spot from a more powerful cartridge” rings true. 300 Remington Ultra Mag.

In this article, I’m going to discuss the history as well as the strengths and weaknesses of the 300 Remington Ultra Magnum in detail. The data used to compare the trajectory and recoil of the cartridges was obtained from Nosler (here, here, and here). Perhaps the biggest difference between the two cartridges is the massive advantage the .300 RUM has in powder capacity though. Make no mistake: the .300 Remington Ultra Magnum is an excellent cartridge. On the other hand, that’s not the case with everybody. There’s no reason you couldn’t use that 180gr Barnes on smaller deer as well. Make sure you follow The Big Game Hunting Blog on Facebook, Instagram, Twitter, and YouTube. Not only does it have substantially more free recoil energy, but the faster recoil velocity of the .300 Remington Ultra Mag makes for a sharper “kick.” Added together, the result can be tooth rattling recoil.