Loaded for Bear - Is 10mm Sufficient?

[soulezoo]

Where I have a tough time accepting this 10mm premis for brown bear defense is that the 10mm doesn't really have that much more penetration than most other duty rounds, but now we propose to use them against a hugely powerful 600+ lb animal, even though the cartridge was designed for use against weaker 200lb animals. Yet, the argument is that it is sufficient because multiple rounds are easier to deliver to the target.

Respectfully, your logic is lacking.

First, in your 9mm response, you are talking about using carefully matched projectiles to the cartridge to the very peak of its performance... compared to the 10mm whose projectiles are often made for the peak of .40 S&W performance which is almost half of what a 10mm can do. Besides, if that magic 12-14" of penetration are all that is desired, and that is what is designed for... then it is a successful design.

The fact is, there are specially designed monolithic projectiles for the 10mm that penetrate beyond 36" in ballistic gel and are more than tough enough to hold up to the large critters hitting bone and what not. I don't think the folks here advocating the g20 are also advocating using generic JHP's that will penetrate 12" and blow up at impact. Show me a 9mm that will penetrate the same and we can talk.

The above does not mean that I am changing my previously held stances in the matter to suggest that 10mm is adequate for brown bear. Only that I believe your thinking is flawed here.

As always, I respect the right of the individual to choose what they feel best. Animal reaction to lead penetration is unpredictable. I recall a story in Outdoor Life when I was a kid about a pair of hunters attacked by a grizzly. They both emptied their 30-30's into the bear (I think I recall over 13 shots.) The bear killed one guy and still escaped only to be killed later by Fish and Game Rangers. The point being, short of a 105mm howitzer, one cannot surely say which caliber will definitely stop said bear.

[Coal Dragger]

Thanks, I realize my logic is not perfect, although the 9mm fmj is a well known over penetrator in use against hostile monkeys.

Because no one has really done controlled testing of a bunch of bullet designs, in a manner acceptable to everyone, with the test set up to to simulate a bear; this debate will be hard to put to bed.

The only comparative test I've found on deep penetration after defeating heavy bone was the Linebaugh test, but phone books soaked in water were the test medium. Everyone here seems to not accept that as a medium for comparing penetration values. Then of course there is the absence of any 10mm bullet being used in those tests.

It would be nice if manufacturers of handgun ammo, who are marketing their product for bear defense would actually do some performance testing and share the results. If they're marketing a loaded round or projectile that can smash through thick leather, a few inches of ballistics gel, then smash a large bone from a cow and keep going for another 30" that would be a pretty acceptable performance I would think.

Rather than arguing about theoretical performance that hasn't been measured in a controlled manner, what would a reasonable series of tests look like to determine minimum effective performance for a handgun bear defense round?

[Coal Dragger]

I know for a fact the 10 mm has sufficient penetration to do the job. The issue is shot placement. You will get off a lot more aimed shots with a 10mm auto than With a 454 revolver. The other issue is bears are just damn hard to kill I know that too. The 10mm approaches the 41 Mag it's not in the same range as other service calipers. A 32 ACP will not give you sufficient penetration unless your very lucky and shoot it in the roof of the mouth.
Basically your argument is for more power with greater tissue damage but with limited potential for follow up shots. That first one better count. What I am arguing for is less power for tissue damage but still enough penetration but with much greater ability to deliver rapid follow up shots. Pick your game plan either can work or fail.

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For the sake of clarification the .32ACP thing was a tangent in use as a duty round for person vs person. Not against bears. If volume of fire is the key.

On the 10mm vs .41 Magnum, when both are loaded to their full potential we both know the .41 is still pushing a heavier bullet faster, and creating more energy. If energy is the metric we want to compare there is still a 300ft-lb gap. Which means the .41 loaded to potential is about 50% more powerful than a 10mm. That's not an insignificant amount.

[Rermey Lee]

I have the opportunity to get a 10mm Glock 20 Gen 3 w/ 5 magazines, OEM sights, and 400 rounds of plinking ammo and 100 rounds of hollow points for $700 trade value (of something I don't really need and have two of)

I have two questions.

Is that a decent deal?

What benefits does a G20 have over a G19? I mean, I know 10mm vs 9mm, but the capacity is the same.

From reading this thread it seems like the G20 has no advantage over the G19 as far as ballistics are concerned?

That depends, you planning on shooting 4 legged critters or 2 legged critters?

[Rermey Lee]

10mm is not enough for Grizzly country, not nearly enough. Black bear is a different story, I've seen a black bear put down with a .357, but it took all six shots to do the job. 10mm is about on par with .357 mag, and no where near being in the same league as .41 mag or .44 mag.

[Uprange41]

For the sake of clarification the .32ACP thing was a tangent in use as a duty round for person vs person. Not against bears. If volume of fire is the key.

On the 10mm vs .41 Magnum, when both are loaded to their full potential we both know the .41 is still pushing a heavier bullet faster, and creating more energy. If energy is the metric we want to compare there is still a 300ft-lb gap. Which means the .41 loaded to potential is about 50% more powerful than a 10mm. That's not an insignificant amount.

Just for context, let's remember that a lot of 10mm carriers went that route because they value the capacity and ease of use over the relative power of a magnum. The .41 doesn't address either one of those, and I'm betting it will have to still be in a gun larger/heavier than the 10mm.

Also, even if the .41 does legitimately give you a 265gr bullet hitting with 1072 ft. lbs. of energy at the muzzle, from a gun that is similar to a 10mm in size, why not then move to a .460 Rowland, which can send a 255gr bullet at 957 ft. lbs. of energy (using Underwood's hard cast loads as a reference for all three cartridges being discussed)? You are legitimately encroaching on the .41 magnum with a load like that, without sacrificing the benefits of the 10mm. And, lets not forget, neither one is even close to approaching a .44, let alone a .454 or greater.

Now, I agree 100% that a universally-accepted testing method is the only thing that will put all of this in context. It would still not answer which is more definitive against a bear, but it would be a relative point of comparison. So that 265gr .41 and 255gr .460*should out-penetrate a slower 220gr 10mm, but to what degree? How much does the wider meplat of the .41 assist vs. the narrower one on the 10mm and .460? Or, more simply, what percentage of strikes on a curved skull will result in deflection or penetration? How many more inches are you getting from the .41 after striking bone?

Without a way to answer questions like that, and drive a person to switch to the "best" performer and embark on that learning/training curve, it still is going to come back down to comfort with the gun vs. comfort with the cartridge.

ETA - just for clarity, I'm using Underwood's hard cast loads as the references, which is why I used energy to compare them. With such similar bullet diameter, weight, and construction, I think it's safe to compare them that way. The loads were;
10mm; 220gr @ 1200 fps / 703 ft. lbs.
.41; 265 @ 1350 fps / 1072 ft. lbs.
.460; 255 @ 1300 fps / 957 ft. lbs.

[Alaskapopo]

Energy is not the metric I would use but rather penetration. At handgun levels we don't have enough energy to even with the super mags to rip tissue past its point of inelastisty. All I care about is that the bullet can penetrate enough to go inside the skull or reach the spine from a frontal charging shot. Before the .44 mag people used the .357 mag for bear defense in a handgun. Again carry what you want. But no matter what you carry don't believe that its the hammer of Thor. We are all making choices based on our training, experience and opinion. I gave mine and I respect others here that disagree with me and I hope no one here has to find out who is right. For entertainment sake I do plan on doing some tests with the Glock 20, a friends short barreled 44, my 454 Ruger. The tests will measure hits on target from the holster and the time will be recorded.
Later

[Spooky130]

Energy is not the metric I would use but rather penetration. At handgun levels we don't have enough energy to even with the super mags to rip tissue past its point of inelastisty. All I care about is that the bullet can penetrate enough to go inside the skull or reach the spine from a frontal charging shot. Before the .44 mag people used the .357 mag for bear defense in a handgun. Again carry what you want. But no matter what you carry don't believe that its the hammer of Thor. We are all making choices based on our training, experience and opinion. I gave mine and I respect others here that disagree with me and I hope no one here has to find out who is right. For entertainment sake I do plan on doing some tests with the Glock 20, a friends short barreled 44, my 454 Ruger. The tests will measure hits on target from the holster and the time will be recorded.
Later

I look forward to the tests... If we are just looking at a comparison of penetration the wet newspaper/phone books would be good. A "standardized" medium is what we need so your test can be repeated.

I'm still of the mind that a 12 gauge or .45-70 lever gun should be a primary defense gun. Back that up with the handgun of your choice. Right now my choice is a 5" 500 SW in a chest holster for ease of access and surety of having on my person. Realizing that bears are tough, fast and unpredictable when in the wild and none of these may ultimately stop a bear intent on ending me. But I will go down fighting...

[QuickStrike]

In dangerous game hunting, a rifle for stopping wounded game is often bigger than the one used for most hunting situations, 416 and up vs. 375 H&H minimum for example.

I wouldnt use a 10mm for hunting brown bear, why would I use it for stopping a charge?

Can glock 20's even reliably cycle those bear rounds? I have read of some malfunctioning with upper end 10mm loads.

Will the test include this ammo?

Hot loads and the flatnose shape are two factors against reliable feeding.

Glock 20's grip is too wide/big for my hands anyway. Even the gen4 and short frame versions. my support hand seperates in rapid fire.

Sold my G20 SF for this reason.

[domestique]

In dangerous game hunting, a rifle for stopping wounded game is often bigger than the one used for most hunting situations, 416 and up vs. 375 H&H minimum for example.

I wouldnt use a 10mm for hunting brown bear, why would I use it for stopping a charge?

Can glock 20's even reliably cycle those bear rounds? I have read of some malfunctioning with upper end 10mm loads.

Will the test include this ammo?

Hot loads and the flatnose shape are two factors against reliable feeding.

Glock 20's grip is too wide/big for my hands anyway. Even the gen4 and short frame versions. my support hand seperates in rapid fire.

Sold my G20 SF for this reason.

Yup. You can buy heavier recoil springs. The aftermarket beaver tail (grip force IIRC), really helps with muzzle flip.