Gun Digest

Handloading: Unlocking The Potential Of The 7mm Rem Mag

The 7mm Remington Magnum is a versatile cartridge that’s well-served by slow burning powders.

The 7mm Rem Mag has a ton of potential other than merely being a hard-hitter if you handload the cartridge.

What Are The Finer Points In Reloading the 7mm Rem Mag

The idea of using a belted case shortened to fit in a .30-06 length action really came to the forefront in the 1950s, with Winchester’s release of the .458, .338 and .264 Winchester Magnums. However, using a 2.500-inch belted case was not an original design. In fact, the idea dates back to 1912, when Holland & Holland released a pair of cartridges that would change the shooting world: the famous .375 H&H Magnum, and the not-so-famous .275 H&H Magnum designed for lighter game.

That .275 Magnum — with a 2.50-inch case and a 7mm bullet — was truly ahead of its time, and though American rifles were chambered for it and American ammunition was available, the cartridge was not a big success here. The concept of a belted 7mm magnum would need until 1962 to ripen, when Remington — presumably in an attempt to ride the wave that Winchester started in the 1950s — would release their 7mm Remington Magnum in the then-new Model 700 rifle. The “new” 7mm magnum had an uncanny resemblance to the .275 H&H Magnum, but history is history, and marketing is marketing, and Remington’s 7mm Magnum has been an unbridled success since its release.

Load Up On Reloading Info:

Shooters have beaten the 7mm vs. .308 argument to death, with both camps having viable points. I’ll avoid that debate, confidently saying that the 7mm bore diameter offers plenty as an all-around choice for general big game hunting. Furthermore, the 7mm Remington Magnum case offers one of the most flexible platforms for the lineup of 7mm bullets, and there’s an awful lot to choose from within that lineup.

Any powder with a burn rate equal to or slower than IMR4350 is a great choice for the 7mm Remington Magnum, up to Reloder 25.

To be a true “all-around” cartridge, I feel it must be capable of taking the majority of our game animals (obviously within the caliber’s capabilities) at any sane hunting distance. The 7mm Remington Magnum can do just that: It has a proper blend of available bullet weight, enough velocity to take larger game at further distances, yet it’s easy enough on the shoulder to allow the shooter to accurately place shots.

Enhancing The 7mm Rem Mag

While there are a tremendous amount of good factory loads available for the 7mm Remington Magnum — it remains on the Top 10 list of most ammunition manufacturers — the true flexibility of the cartridge comes by handloading for it.

It’s not a difficult cartridge to load for; the design is straight-forward, with a 25-degree shoulder for good headspacing — the belt is a carryover from the H&H case and serves no true purpose on the 7mm Remington — and the 0.271-inch-long neck gives plenty of neck tension in spite of the fact that it’s less than one-caliber in length. As a result, crimping the 7mm Remington Mag. is usually unnecessary. The 7mm Remington runs on a large rifle magnum primer, and I have obtained my best results with the Federal Gold Medal Match GM215M.

With a case capacity of 82 grains of water — depending on the brand — the 7mm Remington Magnum will usually run best with a slower-burning powder to take full advantage of the velocity potential of the case. I’ve had great success with Alliant’s Reloder 19 and 22, Hodgdon’s H4350, IMR4350, IMR4451 and IMR8133. This has also come from a variety of bullet weights, from the lighter 140-grain cup-and-core bullets — which are so effective on deer and similar-sized game animals — up to the heavy 175-grain premium bullets, which are perfect for most of the larger game animals on earth.

The author has had very good results with Reloder 22 in the 7mm Remington Magnum.

Powders with a burn rate equal to IMR4350 and slower are a good starting point for the 7mm Remington Magnum, with the slower powders being best suited to the heavier bullets. Reloder 25 is about the slowest I’d go with the 7mm Rem Mag. The slowest burning powders, like Reloder 33 and Hodgdon’s H1000, are too slow to be effective in the 7mm Remington case.

I’ve found neck sizing 7mm Remington brass can have a positive effect on the accuracy of some rifles, though I much prefer using Redding’s Instant Indicator Comparator gauge. This handy little device compares the datum line of fired brass to the SAAMI spec — set by the provided dummy cartridge — to see where the rifle’s chamber sits in comparison to the theoretical dimensions. Once you see the variance between SAAMI specification and the actual chamber, Redding’s Competition Shellholders can make up the difference. This leaves the datum line alone, leaving the chamber dimension from base to shoulder, while allowing the body diameter to be resized for ease of feeding. Even adjusting the datum line 0.002-inch has improved accuracy in the 7mm Rem Mag.

A Very Accurate Magnum

In spite of some reports, I’ve found that the 7mm Remington Magnum can be seriously accurate, with many groups printing sub-MOA and exceptional rifles approaching ½-MOA, sometimes better. The best components usually yield the best results, and I do appreciate the benefits of premium brass, such as Norma, Hornady, Nosler and the like.

Good bullets make a definite difference as well: For deer-sized game I like the Sierra boat-tail Game King, Hornady InterLock and the Swift Scirocco II — especially if shots are closer, as the bonded core will reduce premature breakup and meat damage. For larger game, I’ve had good results with the 160-grain Swift A-Frame and the 175-grain Nosler AccuBond and Partition.

The 175-grain partition makes a good all-around choice in the 7mm Rem. Mag. for large game.

My buddy, Frank Campana, recently asked me to help him develop a load for his new 7mm Remington Magnum; he wanted a single load to hunt a wide variety of game animals. He chose the 175-grain Nosler AccuBond because it would certainly handle lighter game, but it would make longer shots at larger animals easier as well. The higher BC of that bullet resists wind deflection, and that’s always a good thing for distant animals in open country.

We went through several different powders, and while accuracy was acceptable with all of them, we found that his rifle absolutely loved Reloder 23. At a near-maximum load of 63½ grains, we obtained sub-MOA accuracy and a muzzle velocity of more than 2,800 fps. Where some of the faster-burning powders gave excellent accuracy — on par with the Reloder 23 load — the velocities were almost 200 fps lower. Reloder 23 is temperature insensitive, making it a great choice for a hunter like Frank, who may find himself in the Rockies for elk in knee-deep snow or sitting in a leopard blind in the African heat.

If you have a 7mm Rem Mag and want to begin handloading for it, I’ve included a chart of some of my favorite loads. Please don’t jump into the deep end of the pool; as with any data, consult a reloading manual and work up from the bottom, stopping at any pressure signs. These loads were developed in a number of different rifles, and they exhibited no pressure signs in the rifles tested. You may find that it’s difficult to beat the accuracy of some of the factory loads — our modern factory ammo is that good — but you may want to try a bullet that isn’t available from the factories.

The 7mm Remington Magnum is quite a flexible cartridge, and one that will serve a hunter in many different situations. Handloading will give you lots of bench time as you develop your loads, making you even more proficient with your rifle.

Editor's Note: This article originally appeared in the January 2019 issue of Gun Digest the Magazine.

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