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.
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.
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
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. 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.
.257 WEATHERBY MAGNUM ACCURACY
I have shot rifles in about every caliber imaginable through the years, and I am about convinced that some centerfire cartridges have greater accuracy potential than others. Or perhaps I should put it another way: They may not be inherently more accurate, but the rifles chambered for them seem to always respond to a minimum amount of effort on my part by shooting quite accurately. I have yet to work with a rifle in .223 Remington, .22 PPC, or .220 Swift that I could not coax into shooting decent groups. The same goes for the .308 Winchester, .243 Winchester, 7mm STW, and .300 Winchester Magnum. There are a few others, and the .257 Weatherby Magnum is one of them.
I just took a look back at six rifles in .257 Weatherby Magnum I have worked up handloads for in the past. Three are Weatherby Mark Vs, and two are Weatherby Vanguards. The other is a custom rifle on the Remington Model 700 action with a Shilen 26-inch match-grade stainless-steel barrel. Now, get this: Every single one of those rifles delivered sub-MOA accuracy with several factory loads and handloads. The custom rifle consistently shot inside a half-inch with seven different recipes, all loaded with big-game bullets such as the Nosler Partition, Speer Trophy Bonded, and Hornady SST.
In addition to being an extremely accurate cartridge, the .257 Magnum is easy to shoot accurately due to it modest recoil. All of this adds up to make it the finest factory antelope cartridge ever created by the hands of mortal man.
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, a
nd 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 bulletseating 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 freetravel 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.
SHOOTING THE .257 WEATHERBY MAGNUMBULLETPOWDERMUZZLE VELOCITY (fps) 100 YARD ACCURACY (fps) (TYPE)(GRS.)WEATHERBY VANGUARD, 24-INCH BARRELHornady 75-gr. V-MaxH41469.538521.64Nosler 85-gr. Ballistic TipIMR-435069.536531.12Barnes 100-g. XBTReloader 2272.035391.35Nosler 100-gr. PartitionAA 310068.034332.26Nosler 100-gr. PartitionH100078.035341.45Nosler 100-gr. PartitionMRP73.035241.17Nosler 115-gr. Ballistic TipIMR-782869.033060.86Nosler 115-gr. PartitionMRP70.033570.79Speer 115-gr. Bear ClawAA 870086.033140.92Hornady 117-gr. SSTReloader 2571.032590.79Sierra 117-gr. SBTH483167.032061.56Nosler 120-gr. PartitionH87082.033261.15Speer 120-gr. Grand SlamIMR-782869.032531.74Swift 120-gr. A-FrameMRP70.032551.82Hornady 87-gr. SNFACTORY LOAD38631.18Hornady 100-gr. SNFACTORY LOAD35490.92Barnes 115-gr. XFBFACTORY LOAD33411.76Nosler 115-gr. Ballistic TipFACTORY LOAD33840.87Hornady 117-gr. RNFACTORY LOAD33680.91Nosler 120-gr. PartitionFACTORY LOAD34271.43WEATHERBY MARK V, 26-INCH BARRELHornady 87-gr. SNFACTORY LOAD38101.41Hornady 100-gr. SNFACTORY LOAD35881.15Barnes 115-gr. XFBFACTORY LOAD34181.58Nosler 115-gr. Ballistic TipFACTORY LOAD33790.74Hornady 117-gr. RNFACTORY LOAD33801.22Nosler 120-gr. PartitionFACTORY LOAD34100.87NOTES: Accuracy is the average of two three-shot groups fired from a sandbag benchrest at 100 yards. Velocity is the average of six rounds measured 12 feet from the muzzle. Weatherby cases and Federal Gold Medal Match 215 primers were used in all loads. All powder charges are maximum and should be reduced by 10 percent for staring loads on other rifles.NOTE: All load data should be used with caution. Always start with reduced loads first and m
ake sure they are safe in each of your guns before proceeding to the high test loads listed. Since Shooting Times has no control over your choice of components, guns, or actual loadings, neither Shooting Times nor the various firearms and components manufacturers assume any responsibility for the use of this data.
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.