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Is the 10mm Enough Gun for Bear Defense?

Is the 10mm Enough Gun for Bear Defense?
Three of the most practical bear back-up handgun cartridges available are: (from left) Buffalo Bore’s 10mm Auto 220-grain hard-cast load, Garrett’s .44 Magnum 310-grain hard-cast load, and Buffalo Bore’s .480 Ruger 330-grain Dangerous Game monometal load. All are non-expanding, deep-penetrating bullets with wide, flat noses.

Imagine you’re bowhunting caribou in Alaska. It’s early morning and you’re just finishing your morning constitutional behind the designated tree when a commotion and some unfriendly bear-like noises erupt from camp. Hitching your suspenders, you grab your sidearm from the nearby stump and bunny hop frantically toward camp as very human-like screams erupt.

A massive bear with frosted fur is lying across the wriggling body of your hunting partner, and you hear the chilling scrape of Ursus arctos horribilis canines on human skull.

A sound that is half prehistoric battle roar, half paralyzed shriek of terror involuntarily erupts from your throat as you raise your handgun. Faster than thought, the bear whips around, fishhooks into the wind and charges. Well, almost faster. You have time to realize that screaming was a mistake as your gun begins to buck in your palm.

Result No. 1

Your big-bore revolver pounds a heavy bullet into the oncoming bear. The revolver leaps to the sky from recoil but drops smoothly back on target and booms again. Hit hard twice, the bear convulses, hunching like a bodybuilder doing a sit-up, and ends in the fetal position. Huffing spine-melting roars, it sinks to the ground as you sledgehammer it with every bullet remaining in the cylinder of your revolver. With trembling hands, you dig out your Garmin inReach Mini and hit the SOS button, not knowing whether your buddy is alive or dead.

Result No. 2

Your big-bore revolver leaps high in your hands and a spout of earth geysers beside the fast-moving bear. Frantically, you pull it out of the sky and slam the trigger again, then one more time as the bear takes you to the earth. A cloying smell of rot mingles with that of fear and blood and urine as your bowels purge. Now the sound of fang on skull seems to come from inside your brain. Somehow your handgun is gone, and amidst all the shaking and tearing and roaring, you hope that your buddy is alive enough to activate his inReach Mini.

Result No. 3

Rhythmically, your 10mm Auto stitches the oncoming bear with bullets. Dust puffs past him and you know you missed a shot, but most of your shots are connecting. The bear flinches and snaps at its shoulder, folding its chin into its own rich fur, blossoming now with blood and erupting crimson foam with every bone-grinding growl. Fighting the urge to run, you dump the rest of your magazine into the bear’s head and shoulders as it slumps to the ground. With the inReach Mini activated, you move to assist your shredded hunting partner.

Result No. 4

Frantically, you slam 10mm bullets at the oncoming bear in rapid fire. Puffs of dust around it signal you’re missing a few, but with frightened elation, you know some are connecting, too. Not enough to slow the bear, but as it looms close, so big it’s impossible to miss, you’re pointing and pulling fast. Events go to slow motion as the bear knocks you down with its chest, crushing the air from your lungs. Drilled through the skull by one of your last 10mm bullets, the bear lies inert as you fumble for your inReach Mini and blindly hit the SOS button.


Unless we face a situation similar to this, we’ll never actually know which type of shooter we are, although we can—and should—train to be collected, accurate, and fast under pressure. What we can decide is what sort of sidearm we’ll pack in bear country.

Is there one type of backup gun that gives better odds for success?

Traditional wisdom holds that the best backup guns for bear country are powerful revolvers chambered in heavy-horsepower cartridges. Purists suggest that adequate versions begin with the .44 Magnum—and it qualifies only out of polite respect for Dirty Harry.

Many suggest better options are wheelguns chambered for the .454 Casull, .480 Ruger, .500 S&W Magnum, and the like.

The bigger and more powerful a cartridge is the more likely it is to thump a big, angry bruin into submission. And as long as hunters can accurately and efficiently handle one of these big-bore sixguns, they should opt to carry it—particularly where grizzlies are more common than black bears.


Trouble is, few hunters can accurately and efficiently handle one of these big-bore sixguns. To stop a big, fast-moving, aggressive bear with a big-bore handgun, one first has to hit that big bear—and hit it well. Becoming accomplished enough to do this with a big-bore revolver requires diligent practice with a lot of expensive ammunition. Even then, many shooters simply never develop the recoil tolerance and discipline necessary to place accurate shots, let alone accurate shots in fast succession.

The 10mm Alternative

A fairly recent trend has seen increasing numbers of hunters packing semiautomatic 10mm Auto sidearms in bear country. Loaded with heavy, non-expanding bullets, such as Buffalo Bore’s 220-grain hard-cast lead flat nose at 1,200 fps, these pistols are unarguably the most effective semiautos for the task, combining best-possible authority with ease of carry.

These pistols hold two or three times the shots of a big-bore revolver, and most hunters find them relatively easy to shoot accurately and quickly. It’s better, the thinking goes, to put two or three—or six or eight—well-placed smaller bullets into a bear than one or two poorly placed big bullets.

But there is an important caveat: Expanding bullets are out. If you body-shoot an attacking bear front-on, those 10mm bullets must be chosen for extremely deep, straight-line penetration to compromise as many vital organs as possible, and they must shrug off any bone—no matter how massive and dense—encountered along the way. If you head-shoot that bear, your bullet needs to drive through the massive skull to reach the brain and/or spine.

Ideal projectiles tend to be heavy and cast of a very hard lead alloy. Nose profiles should be flat and broad. This imparts shock without impeding penetration and also enables best-possible straight-line penetration with minimal tendency to deflect. The edges of the flat nose should be crisp to enable them to sever arteries and tendons instead of pushing them aside as they pass, like a roundnose bullet. Roundnose designs are also notorious for deflecting off bone. Avoid them.

Last-Ditch Defense

Tyler Freel, an Alaskan who has taken four grizzlies with a recurve bow, offered this sage advice.

“There are a lot of un-sexy factors that take precedence over how powerful a handgun cartridge is…at the end of the day, they’re all still handguns, and we’re all wishing we had a rifle.

“I am a big fan of the 10mm for a bear defense handgun, but there are some premises that need to be understood. Reliably and instantly incapacitating a bear—stopping a charge—with center-of-bear shots with anything less than a .375 Magnum rifle is a joke. Forget any handgun.”

Freel’s remarks are sobering, but they’re also useful.

Remember that bears are much different creatures than hooved, flight-response deer. They are tenacious and are accustomed to fighting.

“A handgun’s role is a last-defense, better-than-nothing shit-hits-the-fan option,” said Freel. “The only shot that will reliably stop a bear right now from a handgun is a brain shot, so a caliber/bullet must be able to penetrate the skull. Situations in which a handgun must be used to stop a bear happen very fast and are extremely stressful and adrenaline fueled. The best chance of stopping a bear is a brain shot or, at least, repeated center-mass shots, which means that accuracy and/or a higher volume of rounds on target is a big deal. The heavy revolvers are more difficult and expensive to shoot, and very few people ever get comfortable with them.”

In the end, only you can decide what backup gun to carry for bears. If you can handle a big-bore revolver with heavy loads, they do offer profoundly more on-impact authority over any other handgun. If you can’t, opt for increased accuracy and rapid-fire capability with a 10mm alternative.

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