Bison (Buffalo) Cartridges

By Chuck Hawks

.405 Win.
.405 Winchester. Illustration courtesy of Hornady Mfg. Co.

Commercial hunting of the North American "buffalo" (actually bison) was widespread from the early 1870's to the early 1880's, by which time the great herds had been largely exterminated. Many different black powder rifle cartridges were used to kill buffalo on the American frontier. The best known and most successful of these were big bore cartridges shooting bullets of .40 caliber and larger. All were loaded with black powder, as smokeless powder had not yet been invented. Because black powder is an inefficient propellant by volume, big cases with large powder charges were necessary and muzzle velocities were typically limited to between 1250-1500 fps.

In those days bullets of all calibers were generally made of cast lead. The only way to increase shocking power was to increase bullet diameter; the only way to increase penetration was to increase bullet weight (and thus sectional density).

The only buffalo cartridge of that era that remains popular today is the .45-70 Government, which was adopted by the U.S. Army in 1873. Like other U.S. service cartridges, the .45-70 became a popular sporting cartridge with American hunters. It was widely regarded as suitable for all North American game, including bison. Remington Arms specifically recommended the .45-70 as a buffalo cartridge for use in their famous Rolling Block rifles.

Plenty of killing power was needed, for the American bison is one of the world's largest bovines, considerably larger than the average African Cape buffalo. While they can indeed be dangerous to humans, the bison does not have the malevolent reputation of his distant African cousin.

It is easy (but dangerous) to underestimate the North American bison, as they appear docile and often are. And everyone knows that they were hunted to near extinction in the late 19th Century. However, what is less well known is that in Yellowstone National Park, the place where human visitors and free roaming dangerous game like grizzly bears and buffalo most frequently meet, bison injure and kill more people than any other animal--including bears.

Make no mistake: hunting the American bison can be hazardous to your health. To quote Glen Derra, manager of the Bar-Y Ranch in Chiliquin, Oregon where free roaming buffalo are hunted, "The cows are most likely to charge because of the calves and will make a pass at you. Whether they hook you or miss, they'll most often keep on going. But, buffalo bulls stay after you until everything is torn to bits and nothing is left; they just don't quit."

Experienced hunters divide buffalo attacks into three categories, behaviors that are apparently common to all of the wild bovine species. If a buffalo is injured or feels threatened it may simply run down the perceived threat and keep going. This is the least serious type of encounter. Sometimes being trampled is fatal, usually it is damaging, but sometimes the victim escapes without serious injury; and occasionally the animal simply misses. The second level of encounter is being hooked and tossed, after which the animal departs. This usually involves serious injury and hospitalization, but the victims often survive if they receive prompt and proper treatment. The most serious attack is a pounding, described in the paragraph above. That is where the animal repeatedly gores and tramples the victim, grinding them into the ground. A pounding is invariably fatal.

Estimates are that there are now around 500,000 bison in North America. According to the published research of Edward A. Matunas, an average size female bison weighs around 930 pounds and an average full-grown male around 1600 pounds. Very large male bison can weigh 2000 pounds and extreme monsters weighting 3000 pounds have been recorded. Anyone hunting game that averages ten times his own weight and solves problems by running over them had better carry a powerful rifle!

Bison are formidable creatures. They can achieve speeds of up to 30 miles an hour and out accelerate a performance car, so a human being cannot outrun a charging bison. Their large front quarters allow them to "slam on the brakes" and stop on the proverbial dime and their smaller rear quarters allow them to nearly turn in place, so a human cannot dodge them if they are committed to his demise. Once engaged, the hunter has no option but to stand and finish the job.

The commercial buffalo hunters on the frontier did their work at ranges safely removed from the great beasts. This is still a wise policy today. A good rule of thumb is to intentionally engage dangerous game no closer than 50 yards and no farther away than 150 yards. The idea is to be close enough to assure a solid hit and far enough away to allow time for a follow-up shot if faced with a charge.

Bison are thick-skinned (CXP4) game. They should therefore be hunted only with powerful rifles. The primary emphasis should be on penetration. Bullets with a sectional density (SD) of at least 0.270 are necessary.

Bison can be taken with modern high intensity cartridges on the order of the .270 Winchester (150-160 grain bullet), .280 Remington (160-175 grain bullets), 7mm Magnum (160-175 grain bullets), .30-06 (180-220 grain bullets) and the various .300 Magnums (180-220 grain bullets). According to information available from some of the buffalo hunting outfitters, and depending on the source, the .270 Winchester or .30-06 or .300 Magnum represent the minimum acceptable caliber (take your choice). However, these are far from ideal.

A step up from any of the small bores, because they throw heavier, larger diameter bullets of adequate SD, would be medium bore calibers such as the .338-06 A-Square, .35 Whelen and .350 Remington Magnum. All of these calibers should be loaded with 250 grain bullets driven at maximum velocity.

I would suggest that the most reasonable cartridges for hunting American bison are powerful medium bores that are also satisfactory for CXP4 class African and Asian buffalo. These start with the .338 Winchester Magnum and include the .338 Ultra Mag, .340 Weatherby Magnum, .358 Norma Magnum, 9.3x62, 9.3x64, 9.3x74R, .375 Ruger, .375 H&H Magnum, .376 Steyr and .378 Weatherby Magnum. The .338's and .358's are generally regarded as being at their best with 250 grain bullets, the 9.3mm's with 286 grain bullets and the .375's with 300 grain bullets.

The traditional type of big bore buffalo cartridges available today include the .405 Winchester (300 grain), .450 Marlin (350-420 grain) and .45-70 +P (350-540 grain). Cartridges of this sort worked in the late 19th Century and they will still work today under similar conditions, particularly when used with modern, high performance powders and bullets.

Bison skulls
Above, a pile of American Bison skulls from 1875. Most of these animals probably fell to the .45-70 Government round.

Due to its size, the bison is the one North American game animal on which the big bore safari calibers are not wasted. Reasonably well known examples of these include the .416 Remington Magnum, .416 Rigby, .416 Weatherby Magnum, .458 Winchester Magnum, .458 Lott, .460 Weatherby Magnum and .470 Nitro Express.

I recently read a summary of the 2003 hunting season at the P Cross Bar Ranch owned by Marion and Mary Scott near Gillette, Wyoming. P Cross Bar Ranch offers fair chase hunting of some of the largest trophy bison in North America. I made notes of the rifle calibers used to bag buffalo (when identified) with the following result: .280 Remington (1 bull), 7mm Magnum (1 bull), .300 Winchester Magnum (1 bull), .338-06 (1 bull), .375 Magnum (2 bulls), .450 Marlin (1 bull), .45-70 (3 bulls), .470 Nitro Express (1 bull), .50 caliber black powder inline muzzleloader (1 bull). Almost all of these animals required two or more shots to put down, irrespective of the caliber used. I suspect that this is because bison have huge lungs that take time to fill with blood even with a perfect shot, and most hunters are inclined to shoot until it is clear that the great beast isn't going anywhere. All of the rifles that I saw in the accompanying photos of downed bison and proud hunters wore telescopic sights.

The understandable exception to the "two or more shots" theme was the record bull (the largest of the year) killed with the .50 muzzleloader; that animal died in about 90 seconds from a single bullet through the lungs. The bullet was found under the skin on the off side, mushroomed to about .94 caliber. This prompted the following editorial comment from the Scotts, "Our client's success with most of the older weapons and bullets has consistently been better than with any of the new weapons and bullets."

Bison, like all CXP4 class game, require tough bullets for reliable kills if heavy bones must be broken. Premium, controlled expansion bullets are usually recommended by the bullet and ammunition manufacturers. The A-Square Dead Tough, Barnes X-Bullet, Hornady Dangerous Game, Nosler Partition, Speer Grand Slam, Speer Trophy Bonded Bear Claw, Swift A-Frame and Woodleigh Weldcore are examples of such bullets. If the bullet can be driven through the ribs and directly into the heart or lungs, standard bullets such as the Hornady InterLock and Remington Core-Lokt may kill faster than the premium bullets, as their greater expansion destroys more lung tissue.

As in all hunting, bullet placement is the key to safe and humane kills. Killing power is important, but it will not compensate for poor shooting. Select a rifle and load that you can shoot with consistent accuracy in the field. If the first shot is a good one there is unlikely to be a problem, even with the biggest trophy bison.

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Copyright 2006, 2012 by Chuck Hawks. All rights reserved.