300 Weatherby Magnum
This cartridge has been around since the mid-1940s, and is probably the best of the large 30-caliber magnums. It has performed splendidly in long-range competition, and is reasonably efficient compared to some of the other big-capacity 30s. The beautifully long neck and graceful double-radius shoulder may be the reason that barrel life is relatively quite good. The belt at the head of the cartridge is a source of false complaints by some inexperienced gun writers that it causes feeding problems. Pure bull. The reason that even fatter cases don’t have a belt, such as the 300 Remington Ultra Magnum, is simply because there is no room for one in a staggered three-round (common) sporting rifle magazine. The lack of a belt also precludes the Ultra Mag series from producing a 458 Remington Ultra Mag. Some gun writers make up things as they go along; possibly because of ego, perhaps to keep their job, or maybe even to get a freebee as a reward.
Since Remington brought out the 300 Ultra Mag in 1999, using the 300 Weatherby as a comparison cartridge in advertising, boasting of over ten percent greater capacity, I figure it’s okay to use the comparison again. Here goes: I like the belt. To me it’s a touch of reassurance that headspace is going to be correct. Essentially, all the belt amounts to is a head-spacing rim moved forward so it’s just in front of the extraction groove. After the first firing, providing the handloader’s sizing die is adjusted properly, head spacing will be made off the shoulder, just like a beltless, rimless cartridge.
The additional capacity of the 300 RUM doesn’t do all that much for for it. Specifically, the 300 RUM has about a 100 fps advantage over the 300 Weatherby but, in owning and testing half a dozen rifles of each chambering over several years, the Weatherby cartridge has proved to be marginally more accurate with heavier match bullets at maximum or near-maximum loads. The 300 RUM rifles tended to produce their best accuracy with bullets of under 180 grains. No real issue here, as both cartridges do perform very well, and rifles do vary insofar as accuracy is concerned. However, the Weatherby does the job with about ten less grains of powder, and it does have a significantly longer neck, both of which likely contribute to the increased barrel life of the 300 Weatherby over the 300 Remington Ultra Mag.
One direct comparison that is hard to refute was the side-by-side of two factory Remington 700 Sendero Rifles; one chambered for the 300 RUM, the other for the 300 Weatherby. The Weatherby cartridge was the better performer in these two otherwise identical rifles. It’s this simple… Remington would likely have been as well off never introducing the Ultra Magnum family. All but the 300 RUM is virtually dead now, with brass for the 7mm, 338, and 375 becoming very difficult to find. The much older (and wiser) 300 Weatherby soldiers on, brushing aside all competitors but the 300 Winchester Magnum. The 30 Nosler and 300 Norma Magnum will possibly become the next victims of the 300 Weatherby and 300 Winchester Magnum team. Let’s take a look in 20 years.
There’s usually a lot of excitement when a new cartridge comes out, which includes a lot of boasting and a few examples of how this or that rifle maker “chose” the cartridge to be chambered in their long-range tactical something or other. Don’t think for even a moment that these claims come without closed-door negotiating sessions, and agreements that include financial exchanges. Think about the Dakota cartridges, the WSSMs, the WSMs, the Lazzeroni cartridges, and other relatively recent developments. It’s not that some of them aren’t good, it’s just that other good cartridges already occupy those spaces. If you are a bolt-action aficionado, and are in the market for a 30-caliber magnum, the 300 Weatherby should certainly be considered.
JDC