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In Praise Of The .257 Weatherby Magnum
by Layne Simpson | January 4th, 2011
From mice to moose, the .257 Weatherby Magnum does it all.
By Layne Simpson
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Of the many cartridges developed by Roy Weatherby, the .257 Magnum was his favorite. Many other hunters have felt the same way down through the decades. Based on annual sales of the various Weatherby cartridges, the .30-378 Magnum is in first place followed by the .300 Magnum, .257 Magnum, .270 Magnum, and 7mm Magnum. Weatherby developed his big .257 in 1944, but before settling on the cartridge we know today, he experimented with .25-caliber cartridges on various cases.
Had the slow-burning powders being produced today been available back then, Weatherby would most likely have stuck with the full-length Holland & Holland case. But since IMR-4350 was the slowest burning powder available, he chose to shorten it to slightly over 21/2 inches. Two other Weatherby cartridges, the .270 Magnum and 7mm Magnum, share that same case.
Like all belted magnums introduced by Weatherby, the .257 Magnum has the familiar double-radius shoulder. As popular opinion once had it, that type of shoulder had certain magical properties that caused propellant gas to flow more efficiently from cartridge case to rifle barrel. Those of us who knew Roy know why he chose a shoulder of such unusual shape: He chose it because he knew it would not be easy for every shade-tree chamber reamer grinder in America to duplicate.
Through the years Roy used the speedy cartridge quite successfully on game as large as moose and elk, and even the mighty Cape buffalo fell with one shot during one of Roy’s many trips to Africa. Declaring war on something as big and potentially nasty as a Cape buffalo with a 100-grain bullet was not something he recommended to others, and Roy did it just once to prove to himself that it could be done.
The .257 Weatherby Magnum has long been popular among other big-game hunters as well, and one has only to read the many customer testimonials published in Weatherby catalogs dating back to the first one in October 1945 to see just how many fans it has had through the years. Roy’s son Ed, who now runs the company, used the .257 Magnum to take a variety of antelope on his first African safari. The list of .257 Weatherby Magnum fans goes on and on.
It is doubtful that many hunters today would use the .257 Weatherby on game as large and as potentially dangerous as brown bear and polar bear, but hunters of yesteryear did it without hesitation. One thing that made the .257 Magnum so effective on big game was the fact that Weatherby was quick to realize most bullets available in the old days were too soft to withstand the tremendous impact velocities delivered by his super-speedy cartridge.
This prompted him to begin offering ammunition loaded with Nosler Partition bullets as early as the 1960s. Doing so made Weatherby the first to offer premium-grade ammunition loaded with what is now often described as controlled-expansion bullets, and I am sure it is the primary reason hunters were able to use the .257 Magnum so successfully on such a variety of game around the world. Back then, two Nosler bullets were offered: a 100-grain Partition at 3555 fps and a 115-grain Partition at 3300 fps. The 100-grain bullet was always Roy’s favorite, and since he promoted it at the drop of a hat, I suspect it was also the most popular weight among his many customers who hunted with the .257 Magnum.
Six factory loadings of the .257 Magnum are offered by the Weatherby company, and all are excellent for their intended purposes. The big cartridge is a bit much for hot-barrel prairie dog shooting, but for reaching across the Back Forty and surprising a distant woodchuck or coyote, the 87-grain loading at 3825 fps will get the job done with room to spare. When zeroed two inches high at 100 yards, it is dead-on at 300 yards and only about half the length of a standing groundhog low at 400 long paces where it is still packing over 1200 foot-pounds (ft-lbs) of energy.
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The .257 Wby., .270 Wby., and 7mm Wby. cartridges are built on a shortened H&H case while the .300 Wby. is on the full-length case.
The 100-grain loading at 3600 fps is a great choice for shooting the smaller big game such as southern whitetails and pronghorn antelope so long as the distance exceeds 200 yards; shoot a deer up close with that one and you may take home more burger than chops. Because of its softness, I will also include the Nosler 115-grain Ballistic Tip in that same category–although it is my favorite when hunting deer and antelope in open country where shots are likely to be out beyond 200 long paces.
At closer ranges, the 120-grain Nosler Partition at 3300 fps is a better choice simply because it will damage less of the eating parts. I also consider it to be the very best choice for any hunter who decides to try the .257 Weatherby on larger game, such as caribou, elk, and moose, at any range. In fact, if I had to do it all from mice to moose with a single factory load in the .257 Weatherby Magnum, it would be the 120-grain Partition.
The factory load with a 117-grain roundnose bullet is a bit of an odd duck because bullets of its shape are not usually associated with an ultrahigh-velocity cartridge such as the .257 Magnum. However, it does have a purpose in the scheme of things. Up until 1964 the barrels of Weatherby rifles in this caliber had a rifling twist rate of 1:12 inches, too slow to stabilize pointed bullets much heavier than 100 grains.
Weatherby offered the 117-grain roundnose because it would stabilize in that twist rate, and the same load is still available for the benefit of those who own rifles built prior to 1964. Due to its softness, that bullet is not as suitable for use on game larger than deer as the 115-grain XFB and the 120-grain Partition.
Pointed bullets weighing 115 grains and up are also better choices than the 100-grain bullet when the wind is blowing rather briskly. Not long back I did some long-range testing of two Weatherby factory loads with the 100-grain Spirepoint and 115-grain Ballistic Tip bullets. Wind velocity ranged up to 20 miles per hour, which is about what you can expect on the typical antelope hunt in Wyoming, a place where strong breezes seem to never stop blowing.
Shooting from the bench, I observed very little difference in wind drift between the two bullets out to 300 yards. But when I switched to 400 yards, I found the 115-grain bullet much easier to keep inside the vital area of the paper target. According to the ballistics charts, wind drift does not differ all that much between those two bullets, but it seems like a lot more in the field.
Note from One Day... : modern offerings from Weatherby are:
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We all like to dream about hunting the biggest game North America offers, but the fact is, for every moose, elk, or grizzly taken each year, hundreds of game animals ranging in size from caribou on down to southern whitetails and pronghorn antelope are brought to bag. The same applies to other parts of the world as well. In Africa, the big stuff, such as Cape buffalo, lion, and elephant, gets all the publicity, but most hunters fire many more shots at plains antelope, such as impala, sable, kudu, and oryx.
The ideal rifle capable of handling all of this does not shoot a bullet bigger than your thumb, nor does it pound your shoulder to a pulp with each squeeze of the trigger. The ideal rifle is one that shoots flat, hits hard, generates a level of recoil easily tolerated by most hunters, and is inherently accurate. What I have described is a rifle in .257 Magnum, and this is why I consider it to be the most useful cartridge in the Weatherby stable.
Recoil, Trajectory & Energy
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The .257 Wby. generates about the same recoil as the .270 Win.
Let’s closely examine each of the three important characteristics I just mentioned. Recoil of a rifle in .257 Weatherby Magnum is about the same as that of a rifle of the same weight in .270 Winchester. More specifically, when a 100-grain bullet exits the barrel of a nine-pound rifle in .257 Weatherby at 3500 fps, one’s shoulder is caressed with 13.5 ft-lbs of recoil. When a 130-grain bullet exits the barrel of a nine-pound rifle in .270 Winchester at 3100 fps, 14 ft-lbs of recoil is generated. In other words, anyone who can handle the recoil of a rifle in .270 Winchester can also handle the recoil of a rifle in .257 Weatherby Magnum.
Then we have the matter of trajectory. Simply put, no big-game cartridge offered by the major manufacturers shoots flatter than the .257 Weatherby Magnum. When a 100-grain bullet exits the muzzle at 3500 fps and is zeroed three inches high at 100 yards, it is about four inches above point of aim at 200 yards, a couple of inches high at 300 yards, and only about six inches low at 400 yards.
There have been times in my life when the .257 Weatherby Magnum has shot so flat as to defy explanation. One of those times was on a recent hunt with Wyoming rancher Marty Tillard. Behind Tillard’s ranch house is a nice benchrest and target butts out to 400 yards, and it was there that I checked the zero of my rifle before heading to the field. I was shooting a Weatherby Vanguard in .257 Magnum and Weatherby factory ammo loaded with the Nosler 115-grain Ballistic Tip.
With the rifle zeroed three inches high at 100 yards, bullets landed an inch high at 300 yards and dead-on my point of aim at 400. Accuracy was minute of angle (MOA) all the way out to that distance. When hunting with that particular rifle and ammunition, I could have held dead-on the vital area of an antelope at any range from just off the toes of my boots all the way out to about 430 yards.
No worrying about how much to hold over or under–I could have simply plastered the crosshairs where I wanted the bullet to go, allowed for wind drift if needed, squeezed the trigger, and the bullet would have been there faster than I could have thought about it. I realize such an incredibly flat trajectory totally contradicts the exterior ballistics charts, but that’s what happened on that day.
Tillard is an avid coyote hunter and made the decision to build a new heavy-barrel rifle in .257 Weatherby Magnum while he was looking over my shoulder through his spotting scope.
The .257 Weatherby Magnum also delivers more than enough energy to cleanly take deer and other game of similar size as far away as any of us should attempt. Right or wrong, 1000 ft-lbs has long been considered the minimum level of energy for quick kills on deer-size game, and the .257 Weatherby Magnum does just that all the way out to 600 yards. At more reasonable distances, meaning inside 400 yards, the distance at which most of us should restrict our shooting, residual energy ranges from 1400 to 1600 ft-lbs, depending on the bullet weight used.
Handloading The .257 Magnum
I know of no American company other than Weatherby presently offering .257 Weatherby Magnum ammunition, but several have taken a stab at other Weatherby cartridges.
Note from One Day... : loaded ammo is now offered by Weatherby, Nosler, Hornady and Norma.
Weatherby ammunition is loaded by the Swedish firm Norma, and it is always considerably faster than Weatherby cartridges loaded by American companies. This is because Norma and other foreign manufacturers commonly load ammunition to higher chamber pressures than American companies.
With this in mind, it is logical to assume that duplicating factory load velocities when using data developed by American component manufacturers such as Hodgdon, Hornady, Alliant, IMR, Nosler, and others would be impossible. Nothing could be farther from the truth. When developing handloads for various rifles in .257 Magnum I have never found it difficult to duplicate the velocity of Weatherby factory ammunition. Regardless of whether the barrel measures 24 or 26 inches, I seldom fail to reach, or even exceed, 3500 fps with 100-grain bullets and 3300 fps with bullets weighing 115 to 120 grains, all loaded to acceptable chamber pressures.
The Vanguard I shot for this report has a 24-inch barrel, and maximum charges of Reloder 22 and H1000 behind 100-grain bullets in it virtually duplicated the velocity of Weatherby’s 100-grain factory load. And the load with Norma MRP was not very far behind. With one exception, the story reads the same for heavier bullets.
The Vanguard averaged 3357 fps with Norma MRP behind the 115-grain Nosler Partition, which compares quite favorably with the 3384 fps I got with factory ammo loaded with the Nosler 115-grain Ballistic Tip. The exception I mentioned earlier is the Nosler 120-grain Partition; my fastest handload averaged 3326 fps, which was almost exactly 100 fps slower than the factory load with the same bullet. In addition to being faster than any of my handloads, it was 25 fps faster than its factory velocity rating.
Handloading the .257 Weatherby is rather straightforward with no pitfalls I am aware of. Like any cartridge operating at high chamber pressures, its case has a tendency to stretch and should be trimmed back to 2.540 inches as required. As primers go, you could probably get by with the standard-force variety with some powders, but I prefer to keep life simple by using nothing but magnum primers in this cartridge. Weatherby factory ammo is loaded with the Federal 215, and the relatively new Gold Medal Match version of that primer is what I now use with great satisfaction.
Then we have the matter of bullet seating depth. For many years, Weatherby rifles chambered for all calibers except the .240 Magnum had chambers with 3/4 inch of freebore, but it was shortened to 3/8 inch during the late 1960s. Overall cartridge lengths for .257 Weatherby factory ammunition is usually close to the following:
Hornady 87-grain SP, 3.090 inches;
Hornady 100-grain SP, 3.145 inches;
Barnes 115-grain XFB, 3.150 inches;
Nosler 115-gr. Ballistic Tip, 3.160 inches;
Nosler 120-grain Partition, 3.160 inches.
I have tried seating bullets out of cases a great deal farther than those lengths in order to reduce free travel in the relatively long chamber throats of Weatherby rifles, but quite often accuracy proves to be worse than when I stick closer to the overall lengths of factory ammo. In the handloads I shot in a Vanguard for this project, I seated the Hornady 75-grain V-Max to an overall length of 3.20 inches, and all other bullets were seated to 3.25 inches.
When developing loads for a rifle in .257 Weatherby Magnum, don’t forget to allow the barrel to cool down after each group is fired. Ambient temperature was in the high 90s when I shot the loads listed in my chart, and after firing only three rounds the barrel would become too hot to touch.
Allowing the barrel of a rifle in this caliber to heat up excessively during sustained firing will shorten its useful life considerably whereas properly cared for, it will last for many hundreds of rounds. (Roy Weatherby once told me that of the many rifles he had sold in .257 Magnum, not a single one had ever been returned to him for replacement of its barrel.) To speed up my velocity/accuracy testing, I cooled down the barrel of the Vanguard between groups by rubbing its exterior surface with ice cubes I had taken to the range in a cooler. This is one of the advantages to having a rifle with a synthetic stock–you don’t worry about getting it wet.
In theory, a 26-inch barrel will produce higher velocities than a 24-inch barrel when both are chambered for the same cartridge. In practice, this is not always true. There are times when actual chamber and bore dimensions of two barrels of the same caliber can vary enough to cause the shorter barrel to deliver velocities just as high and sometimes even higher than the longer barrel. Such was the case with the two Weatherby rifles in .257 Magnum I worked with for this report.
Even though the barrel of the Mark V was two inches longer, it delivered velocities that were higher enough to matter in the field with only one load. Three loads clocked close to the same velocities in the two barrels, and the 87-grain load was actually faster in the 24-inch barrel of the Vanguard.
Given a choice, I would choose a 26-inch barrel for this cartridge, but considering the velocity difference between the two, no hunter should feel handicapped if the barrel of his rifle measures two inches shorter.
Something else I have noticed about rifles chambered in .257 Weatherby Magnum is that they often shoot big-game bullets of various weights to virtually the same point of impact at various ranges. Prior to recent hunts with a couple of rifles of this caliber, I shot both on paper out to 400 yards. Regardless of whether the bullet weighed 100, 115, or 120 grains, both rifles shot them so close together out to 300 yards I could have used them interchangeably during the same hunt.
If I hunted nothing but pronghorn antelope and smallish whitetails and had to do it all with a single rifle chambered for one of the Weatherby cartridges, I might choose the .240 Magnum over the .257 Weatherby Magnum.
The .240 shoots about as flat, is powerful enough to take deer at long range, and it generates even less recoil than the .257 Magnum. But since a good rifleman who is operating under favorable field conditions can stretch the .257’s capability beyond that of any 6mm-caliber rifle to include hoofed game as large as elk and moose, I’ll have to go with it rather than the .240 Magnum.
If I hunted nothing but elk, moose, and brown bear, I would choose either the .300 Weatherby Magnum or the .340 Weatherby Magnum over the .257 Magnum. Both are better for larger game. But for the hunter who mostly hunts deer-size game with no more than an occasional hunt for moose or elk, the .257 Magnum is the clear winner. Anyone who has used the .257 Magnum in the field as much as I have can easily see why it was Roy Weatherby’s favorite cartridge.
Speed Demon 257 Weatherby Magnum
September 30, 2018 by Ron Spomer
The 257 Weatherby Magnum may be the most overlooked, under-appreciated, mild recoiling, flat-shooting, hard-hitting centerfire rifle cartridges you’ve never fired. Perhaps you should rectify that oversight.
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The 257 Weatherby Magnum is the fastest 25-caliber on the market — and has been since 1945.
In a shooting/hunting world obsessed with flat-shooting, wind defying, hyper-accurate, long-range rifles, cartridges that fire .257” diameter bullets have been overlooked. It didn’t used to be that way.
The Surprising History of 25-Calibers and Rise of the .257 Weatherby Magnum
Back in the first third of the 20th Century 25-calibers were quite popular. They began in the late 19th century soon after smokeless powder added enough velocity to offset the weight lost to small caliber bullets. There was the 25-20 Single Shot, 25-20 Marlin, 25-20 Winchester (still around!), 25-21 Stevens, 25-25 Stevens, 25-36 Marlin, 25 Remington and 25-35 Winchester (also still kicking.) But things didn’t really start to sizzle until Charles Newton created the 250-3000 Savage for the Savage Model 99 lever-action rifle. This was the first commercial cartridge to hit the 3,000 fps mark. It had to spit an 87-grain bullet to do this. The year was 1915.
Just five years later A.O. Niedner introduced rifles for his 25 Niedner, the 30-06 case necked down to hold a .257” bullet. This finally became the 25-06 Remington in 1969. Talk about testing the market before taking the leap!
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The 257 Weatherby Magnum on far right is the fastest .25 bore in today’s commercial market, besting the 25 WSSM, 257 Roberts and 25-06 Rem. The Quarter Bores were popular in the first half of the 20th Century. The 257 Weatherby Magnum might gain more fans if it were offered with 1-9″ twist barrels — and high B.C. bullets to match. But, even with today’s options, it outperforms many more popular hunting rounds.
Prior to the commercial ascendancy of the 25-06 Remington, however, there was the 257 Roberts. Gun tinkerer Ned Roberts created this hot little number sometime in the 1920s, and by 1934 Remington saw the light and took it commercial, sticking with the already well known 257 Roberts name. Until the 243 Winchester and 244 Remington appeared in 1955, the 257 Roberts was the dual purpose varmint/deer cartridge of choice across the land.
Clearly, American shooters in the first half of the 20th century were creating a cult of the “quarter bore,” finding it a more-than-sufficient caliber for most North American game — black bears, elk, and moose included. Still, it surprises many to learn that Roy Weatherby contributed to the excitement clear back in 1945. Yes sir. That’s when he shocked the shooting world with his belted 257 Weatherby Magnum.
To put this in perspective, 1945 was the year WWII ended. Hunters were thinking the 257 Roberts was pretty hot stuff, pushing a 100-grain deer bullet 2,900 fps, maybe 3,000 fps at best. Suddenly this Weatherby pops up, belting the same bullet an additional 600 fps. A 100-grain bullet moving 3,600 fps? Oh yeah.
How Roy Weatherby Got 3,600 Fps From His 257 Weatherby Magnum
To reach this speed, Weatherby first made a high volume case by modifying the then popular, belted 300 H&H Magnum. He reduced case length from 2.850” to 2.549”, straightened the side walls, and added his double radius shoulder which was perhaps more showmanship than substance. Regardless, the belted brass case held 84-grains of water and was stuffed with roughly 64 grains of powder. That did the trick. A post-war American shooting public hot for everything fast and powerful (the rocket, jet plane, and atomic bomb had just been invented) lusted for the 257 Weatherby Magnum.
But wait a minute. If it was so fast and alluring, why didn’t it become more popular? Because Weatherby kept if proprietary. You could only buy it in a Weatherby rifle, not a Winchester, Remington, or Savage. Blue-collar Americans lusted after a 257 Weatherby the way they lusted after a Cadillac but drove a Ford.
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For most of the 20th century you had to build custom or buy a Weatherby Rifle if you wanted a 257 Weatherby Magnum. That’s no longer the case, but a Weatherby rifle is still a great option. This Mark V shot sub-MOA with Weatherby factory loads.
Today you can find other rifles chambered for the 257 Weatherby, yet the cartridge still remains less than wildly popular, probably because factory ammunition is limited and rather expensive. Weatherby sells it, of course, and so does Hornady, Nosler, Choice Ammunition, Double Tap, and HSM. Snoop around and you might find more. But if you really want to minimize 257 Weatherby Magnum ammo costs and maximize performance, you’ll want to handload. Price then is about the same as handloading a 30-06.
Modern Powders, Bullets, Pressures, And Twist Rates For The 257 Weatherby Magnum
With today’s slow burning powders in rifles with 26” barrels, handloaders can safely hit 3,576 fps (Nosler Reloading Guide 8) with 100-grain bullets, 3,480 fps with 115-grainers, and 3,400 fps with 120-grain projectiles. Compare that to the top end 6.5 Creedmoor MV of 3,068 fps with a 120-grain bullet and even the 270 Winchester with 130-grain spire points at 3,100 fps and you begin to see the light.
But there’s a catch and it’s abbreviated B.C. Most .257” bullets top out at 120-grains, and at that weight even the really sleek, long boat-tail versions have a hard time breaking .450 B.C. Many 140-grain 6.5mm bullets (.264”) are exceeding .600 B.C. Why not make longer, sleeker, higher B.C. .257” bullets? Because most old, 25-caliber rifles have twist rates of 1-14”, 1-12”, or 1-10” at best. Even Weatherby rifles are saddled with a 1-10” twist in 257 Weatherby Magnum. To fix this you’d have to mount an aftermarket, 1-9″ or 1-8″ or even 1-7.5″ twist barrel on your rifle. (There are some small bullet makers like Blackjack offering high B.C. 130-grain and 131-grain .257 bullets).
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The 25-calibers are handicapped by slow twist barrels that don’t stabilize bullets much heavier than 120 grains. Nevertheless, the 257 Weatherby Magnum pushes them so fast that it outperforms the vaunted 6.5 Creedmoor.
To maximize B.C. in .257, most bullet makers stick with the best form factors they can put in 115- to 117-grain bullets. The results are bullets as long as a 1-10” twist barrel can stabilize. This isn’t all bad, however, because the lighter bullets shoot faster and thus flatter than the 120s.
The highest B.C. .257 bullet I could dig up for 1-10″ twist barrels is the 115-grain Berger VLD Hunting with a claimed G-1 B.C. of .483. We’ll compare it to Hornady’s .264” ELD-X rated .625 B.C. at 6.5 Creedmoor velocities. (G-7 B.C. numbers are a more accurate predictor of performance with the extremely sleek, long, boat-tail bullets, but most shooters are more familiar with G1 B.C. numbers. We’ll stick with those so we don’t confuse readers.)
.257 Weatherby Magnum Versus The 6.5 Creedmoor
We’ll zero both for maximum point blank range with an 8-inch target diameter. This means we’ll zero so no bullet crests higher than 4 inches above point-of-aim. When it drops 4 inches below point of aim, it has reached maximum point blank range for a pronghorn-sized target. Velocities are taken from reloading manuals. Individual handloaders may claim higher MVs than these, but I can’t and won’t sanctify what could be dangerously high pressures in some readers’ personal handloads. We’re sticking with published data. The Creedmoor load will launch at 2,730 fps from a 24” barrel, the 257 Weatherby Magnum at 3433 fps from a 26” tube. Fired at sea level, 10 mph right angle wind.
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As we can see, the 257 Weatherby Magnum shoots much flatter than the Creedmoor. Surprisingly, it hangs right with it in wind deflection. As for energy, the 6.5 Creedmoor carries 1,000 f-p to just beyond 700 yards. The 257 Wby. Mag. carries it past 750 yards. Clearly the 257 is the ballistically superior round to 800-yards. You pay the price, however, in ammo costs and recoil. In an 8-pound rifle, the 257 Wby. Mag. should hit your shoulder with about 21.7 f-p force at 13.2 fps velocity, about like a 270 Winchester. The Creedmoor hits 14.8 f-p at 11 fps velocity in the same 8-pound rifle. For comparison, the 30-06 pushing a 165-grain bullet 3,000 fps generates 26 f-p at 14.5 fps. Compared to the 25-06 Remington, the 257 Weatherby Magnum pumps out roughly 600 f-p more energy at the muzzle and 150 to 200 fps more velocity.
One of the reasons the 257 Wby. Mag. goes so fast is its allowed pressure, 65,000 psi. The 25-06 is limited to 63,000 psi, the 6.5 Creedmoor 62,000 psi.
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The 257 Weatherby Magnum was a factory round for almost a quarter century before the 25-06 Remington came out.
.257 Weatherby Magnum On Game
I haven’t used the 257 Wby. Mag. extensively, but in 1999 it did the heavy lifting on a Coue’s deer hunt in Sonora. I was shooting a light, sleek, custom M700 from Rifles, Inc. that pretty much put all bullets right where the scope reticle looked, sub-MOA. This was the year the first Leica laser range finder came out. Mine said 351 yards. I held dead on and that’s just what the buck became. Dead on the ground. A wide non-typical with palmated main beams, it green scored 121 Non Typical B&C. I liked that rifle so much that I used it to cull a half dozen whitetails and at least that many coyotes. I can’t remember it ever missing, but if it did, it wasn’t the rifle’s fault.
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Sonora Coues buck just back from taxidermist. Alas, the palmated main beams aren’t obvious from this angle, but the 16.5″ inside spread is. I’ve included this poor image only because I hate when writer’s describe a unique deer but fail to show a photo of it. The in-the-field photo is an old slide I haven’t time to find and reproduce here.
About eight years ago a Merkel single-shot in 257 Wby. Mag. sent a 100-grain Barnes TTSX through a 3-inch alder limb and then through both shoulders of a black bear during a hunt with Vancouver Island Guide Outfitters. In Wyoming a genuine Weatherby Mark V rifle in 257 Wby. Mag. made short work of a fine pronghorn buck. I rather regret that I haven’t had occasion to use one on elk or moose. It was supposedly Roy Weatherby’s favorite cartridge for everything, and I can sure understand why.
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A 3-inch thick alder limb wasn’t enough to stop a 100-grain Barnes TTSX fired from a Merkel single-shot rifle in 257 Weatherby Magnum.
If you’re looking for a mild-recoiling, flat-shooting, hard-hitting centerfire rifle you’ve probably overlooked in the past, look to the 257 Weatherby Magnum. I’m betting you won’t be disappointed.
Behind the Bullet: .257 Weatherby Magnum
by Philip Massaro - Friday, January 19, 2018
View attachment 639534 When you hear the word ‘Weatherby,’ speed immediately comes to mind. The signature double-radius shoulder, the belt of brass which hearkens back to its roots in the Holland & Holland cartridges, and huge case capacity are all attributes of the Weatherby series of cartridges. Roy Weatherby began developing the line of cartridges that would bear his surname during the latter part of the World War II, using the .300 H&H Magnum as a basis for his designs.
Weatherby initially shortened the case length to roughly 2.5 inches—allowing them to function perfectly in a standard long-action receiver—for his cartridges below .30 caliber. While the .270 Weatherby Magnum is believed to be the first of the line, the .257 was one of the earlier developments, bettering the ballistics of the .257 Roberts, .250/3000 Savage and then-wildcat .25-06 Remington, by a considerable amount.
The desire to drive a .25 caliber bullet as fast as possible is rather evident throughout cartridge history. The sedate .25-20 Winchester came to light in the mid-1890s, and that bore diameter got a serious facelift in 1915 with the release of the .250/3000 Savage—it was the first commercial cartridge to break the 3,000 fps barrier (albeit with a light-for-caliber 87-grain bullet), and its effectiveness on deer and similar-sized game remains evident to this day. The .257 Roberts—a necked down 7x57mm Mauser case—gave even more case capacity, and corresponding higher velocities. Both are classics, and both are sound designs.
However, the .257 Weatherby Magnum took things to an entirely different place. It will drive even the heaviest .25 caliber bullets—the 117- and 120-grain slugs—to a muzzle velocity of between 3,300 and 3,400 fps, depending on barrel length and manufacturer. This results in a cartridge with a very flat trajectory, and all sorts of kinetic energy for its bore diameter. The belt on the .257 Weatherby serves no purpose whatsoever—it is nothing more than a carryover from the H&H parent case. The double radius shoulder handles all the headspace duties, so that brass belt is for looks alone.
While all that velocity is a benefit for the trajectory, the case capacity of the .257 Weatherby does come with some issues. One, the huge powder charges—often approaching 75 grains of powder—and high velocity will raise hell with the throat of your barrel. The best option to extend barrel life is to do your best to keep that barrel cool—give it some time between shots from the bench. Two, the cartridge is seriously overbore, in fact it’s one of the most overbore on the market. During load development with my buddy’s .257 Weatherby, we could see a bright flame, even under the noon sun, with every shot. A long barrel, say 26 inches or so, will help to get that huge powder column burned within its confines, so you can maximize the capabilities of Roy’s design.
Weatherby ammunition has been, for decades, made by Norma of Sweden, and that’s a good thing. High quality, uniform brass aids in accuracy, and the tolerances that Norma adheres to means very, very few cartridges will fail to function properly—I’ve never had a single misfire from a Norma cartridge. You’ll want a premium bullet for anything larger than a deer, as the high velocities will definitely put a strain on your projectile, especially on the closer shots.
Factory ammunition is available from Weatherby, Nosler, Hornady and Norma, and bullet weights run from 90 grains up to 120 grains, with all sorts of choices for the hunter. The Hornady 90-grain GMX is a sweet monometal affair, fully capable of withstanding the high impact velocities this cartridge can generate. Cruising at 3,550 fps, this should settle the score pretty quickly, and as there’s no jacket or core to separate, penetration will be guaranteed. Hornady also offers the 110-grain ELD-X bullet, which has proven to be ridiculously accurate in many of my rifles (albeit in different calibers), and should be the same in this caliber. Nosleroffers the AccuBond, Ballistic Tip and Partition, so you can have a choice of performance suited to the game you’re after. Weatherby lists, among others such as the Nosler projectiles, the Barnes TTSX bullet at 80 and 100 grains; not only are these bullets strong, but the lighter weight will allow for an increase in velocity.
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Should you choose to handload the .257 Weatherby, you’re definitely going to want to choose the slowest burning powders, and spark it with a good large rifle magnum primer. RL-25, IMR7828, and other slow burners have all given good results in the .257, though I will note that bullet seating depth can play an important role in finding the best accuracy.
The limits of the .257 Weatherby are essentially up to the shooter. Roy Weatherby used this cartridge to kill a rhinoceros—though I would highly advise against such utter foolishness—but I feel that elk and perhaps moose represent a better top end of game animals, again, when mated with premium bullets. Nonetheless, if you’re a fan of the quarter-bores, the .257 Weatherby Magnum will perform above and beyond what you’d normally expect from this bore diameter.
Norma Cartridge of the month: .257 Wby Mag
Written By: Aaron Carter
If a well-versed hunter was asked to describe what he or she deemed to be the ideal whitetail or western big-game cartridge, assuredly “high velocity,” “flat trajectory,” and “hard hitting” would top the list. Interestingly, all of the aforementioned attributes—and then some—are found in a cartridge that turns 70 years old this year; that cartridge is the 257 Wby. Mag.
Although not the first cartridge in the once-proprietary “Weatherby Magnum” series—that distinction goes to the 270, which was introduced in 1943—the 257 Wby. Mag.’s popularity approaches that of the much-vaunted 300. Exuding Roy Weatherby’s “high-velocity” mantra, it is purported to have been his personal favorite; in fact, he used the cartridge to take game in size up Cape buffalo, though such is not recommended. Because of its impressive external and terminal ballistics, yet mild recoil, it’s among my favorite cartridges, too.
When the 257 Wby. Mag. debuted, there were relatively few true “high-performance” factory or wildcat big-game cartridges; in this realm, the 270 Win. reigned supreme, though Weatherby’s own 270 bested it by more than 250 f.p.s. In “quarter bores,” as they’re often coined, the two factory options best suited for stretching the distance at the time were the 250-3000 Savage (250 Savage) and 257 Roberts, which offered—and still do—respectable downrange performance. Both chamberings would eventually be “improved,” a process derived by P.O. Ackley that increased usable propellant space through the reduction of body taper and steepening of the shoulder angle, and resulting in a velocity increase upward of 200 f.p.s. Still, the 257 Wby. Mag. offered a marked improvement over its cohorts; in fact, depending on the projectile’s weight, the increase in velocity ranged from 300 to 600 f.p.s. Due to the Weatherby’s cavernous case (approximately 81.0 grs. of water), the largest gains were realized when long, heavyweight bullets—weighing upward of 120 grs.—were utilized.
Unlike the aforementioned factory chamberings, though, several wildcats approached, if not eclipsed, the velocities of the 257 Wby. Mag. Take the 25 Neider for example. Unveiled in 1920 by A.O. Neider, the 25 Neider—or 25-06 as it would be named upon its adoption by Remington in 1969—offered velocities within 200 f.p.s of the Weatherby round across the bullet weight spectrum. Even today, when the most technologically advanced propellants are used, the 25-06 Rem. still fails to catch up to the 257 Wby. Mag. The latter’s case—the same as used for the 270 and 7 mm Wby. Mag. cartridges, albeit necked down—offers about 22-percent more propellant capacity the 25-06 Rem., which, when combined with a high pressure ceiling, gives it an undeniable advantage with regard to external ballistics.
In his book Handbook for Shooters & Reloaders II, P.O. Ackley describes several .25-cal. wildcats with velocities that exceed those of the 257 Wby. Mag. The most intriguing chamberings are the 25 ICL Mag. and the 257 Baker Mag.—both of which employ a necked-down 264 Win. Mag. case to achieve 3,790 f.p.s. and 3,650 f.p.s., respectively, with a 100-gr. projectile. Based upon the propellant types (burn rates) and charges necessary to attain those elevated velocities, it’s possible that they were overpressure, not to mention considerably less efficient that the 257 Wby. Mag., which is already considered overbore. Then again, “efficiency” is not what the 257 Wby. Mag. or other high-performance cartridges are about.
As with 0.277” bullets, which are used in cartridges such as the 270 Win., 270 WSM, and 270 Wby. Mag., traditionally most .25-cal. bullets—which typically weigh between 75 and 120 grs.—have been less streamlined than those in 0.243”, 0.284”, and 0.308” diameters. As such, the less aerodynamically shaped projectiles shed velocity more quickly. This not only decreases the amount of energy delivered on-target, but also increases bullet drop and wind deflection, which are critical considerations for hunters who have the skillset to “go the distance.” Fortunately, companies such as Berger, Nosler, and Sierra have increased the number of .25-cal. hunting bullets exhibiting increased ballistic coefficients. For example, when a 115-gr. Nosler Ballistic Tip (with a .453 BC) is propelled to 3,380 f.p.s., and the rifle is zeroed at 300 yds., the bullet hits 7.90” low at 400 yds. and 21.50” at 500 yds. Talk about flat shooting!
Before selecting a projectile, one must determine whether or not the rifle that he or she is using has the appropriate rate of twist to stabilize it. If your 257 Wby. Mag. has a 1:10” twist, all .25-cal. bullets are fair game; however, if the rifle has 1:12”, such as found on some older Weatherby rifles, the heavier, streamlined projectiles will not stabilize. Weatherby’s antidote for the dilemma is its 117-gr. round-nose load, which works equally well with both twist rates. Also, if “working up” loads for a custom-chambered 257 Wby. Mag., note that it likely doesn’t have Weatherby’s lengthy freebore, so pressures can climb more quickly.
When pursuing deer-size game where long shots are probable, the best bullet options are the Norma 100-gr. spritzer; Berger 115-gr. Match Grade VLD Hunting; Nosler 110-gr. AccuBond, 115-gr. Ballistic Tip and 115-gr. Combined Technologies Ballistic Silvertip; and Sierra 100- and 117-gr. spitzer boattail GameKings. At close range, though, expect these cup-and-core bullets to expand violently, thus causing considerable damage to edible meat; as such, a controlled-expansion projectile, such as the Nosler Partition, Speer Grand Slam and Swift Scirocco II or A-Frame, would be preferable for closer shots. In lead-free bullets, Nosler has a 100-gr. E-Tip and Barnes has the 80- and 100-gr. TTSX, and 100- and 115-gr. TSXs. Due to their homogenous construction, these projectile retain most, if not all, of their pre-expansion weight; in fact, controlled-expansion lead-core bullets with heavier starting weights will oftentimes weigh less after expansion than the all-copper Barnes bullets due to material being “washed off.” Given their high weight retention, penetration is quite deep. The 115-gr. TSX, as well as the 115- and 120-gr. Nosler Partitions, are the preferred projectiles for pressing the 257 Wby. Mag. into service as an elk cartridge. With this, precision shot placement is imperative.
The bullet that I prefer “across-the-board” for big-game hunting with my 24”-barreled Weatherby Vanguard Series 2 Synthetic is the 115-gr. Partition, which is propelled to 3,240 f.p.s. using 70.5 grs. of Reloder 25 ignited by a Federal Gold Medal 215 Match (GM215M) primer, all contained with a Weatherby (Norma) case. Using this load, my best three-shot group at 100 yds. to-date measured 0.493”, and I’ve yet to have to track a single Virginia whitetail deer that I’ve used the combination on—all either dropped on the spot, or within sight. Seeing the Partition’s terminal performance, I wouldn’t hesitate to shoot an elk with the combination. For the 257 Wby. Mag. owner who wants to pursue elk, there’s no need to purchase another rifle, just match the bullet to the quarry and pick your shots carefully.
Lightweight, lightly-constructed .25-cal. bullets—with most weighing between 75 and 85 grs.—purpose-built for varmint and predator hunting are widely available, though rapid throat erosion and the cumulative effect of felt recoil preclude the 257’s use on a prairie dog town. That being said, the 257 Wby. Mag. has found favor with diehard predator hunters and ranch hands. Why? The cartridge’s high velocities—in excess of 3,800 f.p.s. with an 85-gr. Nosler Ballistic Tip—combined with heavier bullet weights result in less drop and wind deflection, making first-round, long-range hits on call-shy foxes and coyotes surprisingly easy. Depending on the individual bullet’s construction and its path, pelt damage could be considerable.
As for propellants, the 257 Wby. Mag. achieves its highest velocities with large doses of the slower-burning variants. In the Norma line, the nod goes to MRP and MRP-2, whereas other good options are IMR-7828, H-1000, Ramshot Magnum, and Alliant Reloder 22 and 25. The latter is my preferred propellant for the chambering.
Factory-loaded ammunition in 257 Wby. Mag. is less widely available than many other “mainstream” cartridges; however, its performance is worth the price. In its American PH line, NormaUSA offers a quality, yet economical, 100-gr. spitzer load. Norma also loads the projectile for Weatherby, as well as the Hornady 87- and 100-gr. Spire Points, and a 117-gr. round nose, all of which are InterLocks. Additionally, it offers Barnes’ 80-gr. TTSX and 100-gr TSX, and lastly, from Nosler, the 110-gr. AccuBond, the 115-gr. Ballistic Tip and the 120-gr. Partition loads. There are ammunition options for every species that 257 Wby. Mag. is capable of ethically taking. Norma also offers premium component brass under both the Norma and Weatherby names.
Due to its impressive external and terminal ballistics, the 257 Wby. Mag. is the quintessential “bean field” and western big-game rifle; in fact, it’s unlikely that one could find a chambering more well suited to long-range hunting. With today’s increased emphasis on, and desire to, stretch the distance, it’s interesting that this 70-year-old cartridge is optimally suited to do just that. And best of all, it does so without objectionable recoil.
