My dad became a life member of the NRA when I was still in diapers, and from the time I can remember, there were several copies of the American Hunter hanging around the house at any given time; in fact, there still are to this day. Ol’ Grumpy Pants had but one big game rifle for decades—a battered Mossberg bolt gun chambered in .308 Winchester—and still uses it with great effect, but the much younger me would pour over those pages and soak it all up like a sponge. Numbers and names, histories and ballistics, and all the subtle details that went along with it mesmerized me, and I probably drove the old man nuts with a thousand questions. I remember reading two words that just seemed so damned cool to me: belted magnum.
The .300 Win. Mag. is based on a shortened H&H case.
Mind you, at the time I hadn’t even fired his .308, but I was undeniable intrigued with it all. I drew a correlation from the lineup of fantastic articles written in the late 70s and early 80s; the belted magnums had more horsepower (and recoil) than did standard cartridges. Plus, that belt of brass just above the extractor groove looked really cool. So, picking Dad’s brain, he explained that the belt gave the case extra strength (sorry Pop, that wasn't correct) and the additional case capacity gave a boost in velocity, which he felt was unnecessary for our neck of the woods. Later in life, when we started to hunt abroad, Dad saw the wisdom of the .300 Winchester Magnum for longer shots on caribou in Quebec, and after that went down the rabbit hole by jumping to the speedy .300 Remington Ultra Magnum.
So, what makes a magnum? Does the magnum cartridge need to be belted? What are the advantages/disadvantages of both designs? Let’s take a look, and hopefully it’ll help you make a more-informed decision.
Despite identical ballistics, the .416 Rigby doesn't have the magnum name, but the .416 Rem. Mag. does, carried over from the parent cartridge.
The word ‘magnum’ is a derivation of the Latin word magnus, meaning ‘great’. In the wine community, it refers to a larger-than-normal bottle size, and in the shooting world it refers to a cartridge which offers an enhanced performance level. In order to give an enhanced performance, one would have to assume that there was some sort of standard benchmark against which the magnum cartridge can be measured. I often wondered why the .416 Rigby wasn’t a magnum, and I assume that because there was no prior standard cartridge in that bore diameter, it defined the standard. Sometimes, I think cartridges based on a magnum case inherit the magnum moniker, such as the case in the .416 Remington Magnum, which is the ballistic twin of the Rigby, but is based on the belted magnum case.
Accordingly, the first belted case was 1905’s .375 Velopex, also known as the .400/375 Belted Nitro Express. If this helped define the performance level of a .375-bore cartridge, it is easy to understand why the 1912 release of the .375 H&H Belted Magnum is a magnum. The belt itself is nothing more than a means of headspacing a cartridge; the belt acts like a small rim, yet the design feeds much easier from a box magazine than does any rimmed cartridge. The .375 H&H, and its younger brother the .300 H&H, each have a relatively large case capacity, and were the perfect platform for wildcatters to use for the development of our most popular magnums, including the .300 Winchester and Weatherby Magnums, 7mm Remington Magnum, .338 Winchester Magnum and .458 Winchester Magnum. The belt is still used for headspacing, though it does pose certain issues.
The classic .375, one of the oldest belted magnums.
For the straight-walled cases, like the .458 Winchester Magnum and .458 Lott, it is absolutely necessary, but for those with steeper shoulders, like the .300 Winchester, you’ll notice case stretching after firing, with the shoulder moving forward, expanded to the chamber dimension. Those who reload the bottle-necked belted magnums quite often limit the amount of case resizing, in order to let the cartridge’s shoulder handle the headspacing duties, and an improvement in accuracy due to better concentricity and alignment is often seen. Not that the accuracy from factory ammunition (headspacing on the belt) is terrible, but you can see the case stretch as much as .020 inches. If you only shoot factory ammo, this may not make a bit of difference to you.
The beltless magnums—most of the time based on larger rimless cartridges like the .404 Jeffery—use the shoulder for headspacing, just as the .270 Winchester and .30-06 Springfield do. The .338 Lapua Magnum is based on the .416 Rigby, and the .28 Nosler and .300 Remington Ultra Magnum are based on the .404 Jeffery, as is the old Dakota series of cartridges and (loosely) the Winchester Short Magnum series. This group of cartridges is wonderfully accurate, and give extended case life in comparison to their belted counterparts. While all cases stretch to a certain degree, the belted magnums will—after a number of firings—demonstrate case stretching and even separation just above the belt.
The 26 Nosler and 33 Nosler are based on the .404 Jeffery.
Which design makes the most sense? Well, I've loaded for and hunted with both designs for decades, and I don’t really have a preference. There are those who feel the belted magnum has had its time in the sun, and is destined for obsolescence, but each year sales of the 7mm Remington Magnum, .300 Winchester Magnum and .375 H&H Magnum hold steady. Having had two decades to unseat the .300 Winchester Magnum, I don’t see the .300 Winchester Short Magnum selling better than its belted cousin. But, the beltless 6.5 PRC (giving magnum performance in spite of its name) is gaining a head of steam among hunters and long-range shooters alike.
Despite being 109 years old, the .375 H&H Belted Magnum isn’t going anywhere, despite the .375 Ruger’s beltless case and identical ballistics. And though I feel it is slightly overbore and inefficient compared to the .280 Ackley Improved, there will be a ton of 7mm Remington Magnum rifles headed afield this fall, and the next, and the next. Let’s settle the debate like this: if you don’t handload your ammo, it probably doesn’t matter whether or not your cartridge has a belt. If you do, and case life is important to you, opt for the beltless magnum designs. Personally, I’ll happily be using both.