Hot Tips for Reloading the 7mm STW

Hot Tips for Reloading the 7mm STW

Reloading the 7mm STW - 1Reloading the 7mm STW is not an overly complex process, but it's often necessary given the cartridge's lack of widespread popularity and availability. Here are a few tips for those looking to load their own.

Cartridge trends come and go, as each year we see a new cartridge released that is guaranteed to be the best thing since toilet paper. As time has proven, some are totally valid designs, and some go the way of the dodo. While I’m not about to speculate as to why some major companies release or back a particular cartridge, only to abandon the prospect of producing ammunition for those customers who have purchased rifles in that chambering, it happens. One example is the 7mm Shooting Times Westerner (STW). It was touted as the baddest 7mm Magnum available, and Layne Simpson, who had a huge part in its design, wasn’t wrong in that assessment.

But development of cartridges like the Remington Ultra Magnum series, coupled with the huge marketing capabilities that the big players possess, can push the perfectly viable cartridges, perhaps of a lesser pedigree, off the stage. Does that mean that the 7mm STW is any less of a cartridge than it once was? Certainly not.

Just as the .300 Holland & Holland has been pushed into “specialty-affair” status by the .300 Winchester Magnum, it doesn’t mean that the Super .30 is any less super, it just means ammunition is more difficult to come by. There are a few 7mm STW loads still available, but they’re few and far between.

What to do if you’re a fan and love your STW rifle? Well, friends, that’s where the reloaders come into their own. Here are a few tips to get you started in reloading the 7mm STW.

Reloading the 7mm STW - 3Get the Right Dies & Brass
The 7mm STW is a relatively straightforward affair, being a belted cartridge maintaining the 2.850-inch case length of the .375 Holland & Holland, as does its parent cartridge, the 8mm Remington Magnum. You’ll obviously need a set of dies — I happen to have a set of Redding dies for the 7mm STW — but you’ll need to procure some brass.

Unfortunately for the STW fans, sources of new component brass are drying up. Fortunately for the STW fans, Nosler has some foresight, and offers its excellent component brass for reloading the 7mm STW. One thing you need to know about Nosler brass: Right out of the box, it’s ready to load; it’s all nicely chamfered and deburred. I can’t say that about too many other brands.

Use a Slower-Burning Powder
The STW has a large case capacity for its bore diameter, so to get a good balance of uniformity and velocity, you’ll have to look at powders on the slower side of the spectrum. For a cartridge of these proportions, I like any powder with a burn rate equal to or slower than that of IMR4350, as it will fill the case well and provide the pressures needed to move bullets at the velocities they were intended to move.

Another interesting point I’ve observed over the years is that these higher velocity cartridges seem to show the best accuracy with bullets in the middle to heavy end of the weight spectrum for that particular caliber. For reloading the 7mm STW and addressing its larger case capacity, you’ll need a large rifle magnum primer, in order to consistently ignite that powder column.

Choose the Right Bullet for the Job
A friend of mine needed to fuel his STW, and none of the factory offerings were really doing what he knew this rifle was capable of doing, so he called me to handload some ammo for him. He didn’t really have much of a preference as to bullet type, so I suggested we try and keep it simple and find a bullet that will both reach out well for the longer shots that the 7mm STW handles so well, yet is strong enough to maintain integrity on the closer shots with higher impact velocities.

My suggestion was easy: the 150-grain Swift Scirocco II. This is a bonded-core bullet with a black polymer tip, a thick, tapering jacket and a good boat tail for a higher ballistic coefficient.

My experiences with this bullet have been nothing but positive, especially in those cartridges that can really throw a fastball, like the .300 Winchester Magnum and both the 7mm and .300 Remington Ultra Magnums. They are very accurate, often shooting less than ¾ MOA in a well-tuned rifle, and their high ballistic coefficient will help to retain as much energy as possible, as well as give good trajectory and resist wind deflection.

Perusing the Swift reloading manual, they indicated that the powder that gave the lowest deviation on velocity in the 7mm STW is Hodgdon’s H4350, and that makes perfect sense in a case like this. Spark this powder with a good large rifle magnum primer — my own personal choice is the Federal Gold Medal GM215M — and you’ve got a recipe for success.

Reloading the 7mm STW 4The 150-grain Scirocco has a total length of 1.385 inches, and due to the maximum overall length of the 7mm STW at 3.600 inches, that fact translates into seating the bullet deep into the case, almost to the point where the beginning of the ogive meets the case mouth, but not quite. Mating it with Hodgdon’s H4350 gave good velocities and a decent amount of room for seating the long, boat tail bullet. Velocities with this powder will run just over 3,100 fps and will do very well across a canyon or out on the prairie flats.

Were I asked to provide ammunition for this cartridge for use against animals larger than moose, I’d probably opt for a heavy-for-caliber 175-grain bonded core bullet, but for most of the work the 7mm STW is asked to do, the 150-grain Scirocco will suffice very well.

Parting Thoughts
The 7mm STW is one of the many children of the .375 H&H that has its father’s belt of brass, but headspaces off the shoulder, rendering that belt useless. It does retain the same 25-degree shoulder of its big brother, the 8mm Remington Magnum, so headspacing is not an issue at all.

If you want to try and tighten groups up even further, the Redding Deluxe Die set comes with a neck-sizing die, so you can make some custom ammunition for your own particular STW rifle, and I’ve had good results going down that road in similar cartridges, especially for long-range work. Just remember, neck sizing restricts the ammunition you create to the rifle in which it was fired, as the body of the cartridge will be a mirror image of that one particular chamber.

The 7mm STW is just one of the many victims of the sad saga of cartridge obsolescence, but we, the reloaders, can keep the fire burning brightly. Hoard that brass, and shoot on!

Editor's Note: This article is an excerpt from the May 2017 issue of Gun Digest the Magazine.


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