Glock 20 10mm hard cast bullets or FMJ?

[jeff43]

I’ve been doing some reading on loads for bigger game such as bears with a 10 mm. Why do they suggest hard cast lead bullets instead of FMJ bullets? 

[DocHawk]

The unwritten shorthand is that the hard cast bullet is assumed to have a flat, wide meplat with sharp edges for similar penetration to FMJ but better wound channel creation. 

The problem is - and is seldom addressed - is that the best bullet design with a purely flat meplat would probably not feed reliably out of a semiautomatic.

A deep penetrating, expanding JHP is not a bad choice for bear, in my opinion. Most LE "barrier blind" rounds (another misnomer) would do well. Think Hornady Critical Duty. 

Sacrilege, they say. Well, "they" probably haven't actually read the scholarly study of human/bear encounters that concluded every single person who actually employed their firearm against the attacking bear, survived - and almost all without injury. *Most* of those engagements were with 9mm and 40S&W law enforcement ammo. The one guy who shot his bear and survived with the most serious wounds did so with his toes shot off - he put his legs up in defense, and proceeded to shoot the bear through his own feet in the heat of the moment. Another pair of guys got thrice pounced by a very determined grizzly, and successfully drove him off (3 times) with an itty bitty micro 9mm carry handgun.

A fascinating study, well worth the read. I'll come back and link it if I get around to it. The moral of the story is, it matters more how you carry and whether you draw, than precisely what you draw.

Having said all that, I run high pressure/high velocity 10mm JHP out of a 4.6" M&P 2.0 10mm when I'm in the woods. And sometimes even when I'm not!

 

Edited January 25, 2023 by DocHawk

[JustEd]

Leading 

[Darrell]

I have no experience with a Glock 20, but the factory does not recommend lead bullets for the Glocks I own. This is due, as I understand it, to Glock's use of polygonal rifling in their barrels.  I've shot lead bullets through my Glock 45 and 9mm with no ill-effect, though.

[jeff43]

They were saying  to shoot something like a hard cast lead bullet that would not expand to punch through bones and the scull , so why not FMJ bullets was what it was curious about.

[chances R]

poly coated bullets would be a good alternative to Lead cast.  Seems to me that a jacketed soft point would be a good choice.

[DocHawk]

Here are the findings of Dean Weingarten's study, Handgun or Pistol Against Bear Attacks (2021)

104 cases, 97% Effective

Key Takeaways

• Pistol shots stopped 97% of the bear attacks.
• 12.5% of shooters were injured after firing on the bear.
• Weaker ammo needed more shots to stop the attack than stronger ammo.
• Hollow points needed more shots; multiple reports cited them glancing off of bear skulls.
• The 4 failures: .22lr vs. polar bear, .38 special vs. black bear, .357 Magnum vs. grizzly bear, .45 ACP vs. black bear.
• 5 incidents were initiated by dog(s).
• Dogs assisted in 2 incidents, buying time for the owner to fire.
• Several successful uses of firearms followed the failure of pepper spray.
• Warning shots were successful about half the time they were tried.
• Aiming for the heart or lungs was highly effective

By the way, this is in direct conflict with the "use bear spray" results you'll get if you google "firearm or bear spray vs bear." Notice who posts and parrots those results: typically progressive, liberal, and conservationist sources. The most-often cited studies on these pages are BYU's 2012 study, which found firearms generally ineffective and bear spray 97% effective. However, dissecting their methodology reveals a grossly biased study, where incidents in which a person carrying a gun but not drawing it were counted as gun failures, but only incidents with ideal conditions in which the bear spray was deployed prior to close contact with the bear were counted. When the samples are evaluated using similar deployment criterion, the statistics are reversed.

Bias in science, sucks.

[Choatecav]

4 hours ago, DocHawk said:

Here are the findings of Dean Weingarten's study, Handgun or Pistol Against Bear Attacks (2021)

104 cases, 97% Effective

Key Takeaways

• Pistol shots stopped 97% of the bear attacks.
• 12.5% of shooters were injured after firing on the bear.
• Weaker ammo needed more shots to stop the attack than stronger ammo.
• Hollow points needed more shots; multiple reports cited them glancing off of bear skulls.
• The 4 failures: .22lr vs. polar bear, .38 special vs. black bear, .357 Magnum vs. grizzly bear, .45 ACP vs. black bear.
• 5 incidents were initiated by dog(s).
• Dogs assisted in 2 incidents, buying time for the owner to fire.
• Several successful uses of firearms followed the failure of pepper spray.
• Warning shots were successful about half the time they were tried.
• Aiming for the heart or lungs was highly effective

By the way, this is in direct conflict with the "use bear spray" results you'll get if you google "firearm or bear spray vs bear." Notice who posts and parrots those results: typically progressive, liberal, and conservationist sources. The most-often cited studies on these pages are BYU's 2012 study, which found firearms generally ineffective and bear spray 97% effective. However, dissecting their methodology reveals a grossly biased study, where incidents in which a person carrying a gun but not drawing it were counted as gun failures, but only incidents with ideal conditions in which the bear spray was deployed prior to close contact with the bear were counted. When the samples are evaluated using similar deployment criterion, the statistics are reversed.

Bias in science, sucks.

Excellent data here.  Thanks, Doc.

[ohell]

Hard cast is one material that’s the same all the way through.  No jacket to separate, better penetration chance. Jacketed bullets are like m&m candy (not woke yet) but hard outside and soft inside.  Most of your jacketed bullets are produced for 40s&w velocity.  Your 40 cal will be full of flat nose options but generally hard cast have larger meplat to crush tissue and jacketed have round nose and smaller meplat pushes tissue aside.  so generic caliber answer - hard cast is better choice for penetration with damage over round nose or hollow point.
 
leading at 10mm velocity with heavy bullet, meh. Ignore IMO even in Glock barrel 

consider the solid copper penetrating bullets too and stick with boutique ammo.  The big box brands are like hot 40s&w loads. 

[myg30]

On 1/25/2023 at 7:11 AM, Darrell said:

I have no experience with a Glock 20, but the factory does not recommend lead bullets for the Glocks I own. This is due, as I understand it, to Glock's use of polygonal rifling in their barrels.  I've shot lead bullets through my Glock 45 and 9mm with no ill-effect, though.

Morning all, Darrell, check out the Castboolit forum where the myth of lead in Glocks is debunked. A properly sized cast and loaded lead bullet shoots just like jacketed bullet in a Glock. 
Mistakes and sloppiness in any type of reloading jacketed or cast bullets leads to failures in any firearm. 
‘My last sentence on the reloading forum was “ If you’re in a hurry to reload, DONT” !!

 

 Mike

 

[Nikiski Dave]

I use hard cast lead in 357, 45acp and 10mm. They work.

[jeff43]

40 minutes ago, Nikiski Dave said:

I use hard cast lead in 357, 45acp and 10mm. They work.

What brand bullets are you using on your 10mm?Where do you get them?

[Choatecav]

Often, when I am riding horses in the wild country, I carry my Glock 20 but the ammo that I use with it is the Underwood Extreme Penetrator.  While not cast lead, it is solid copper bullet and is a beast.  I don't ride in areas that have bear, but would it not also have the same effect on a large animal skull like that of a bear? 

Here is a link to the ammo.

10mm Auto 140gr. Xtreme Penetrator® Solid Monolithic Hunting & Self Defense Ammo (underwoodammo.com)

 

[Nikiski Dave]

3 hours ago, jeff43 said:

What brand bullets are you using on your 10mm?Where do you get them?

I use Meister or Hunter Supply.

[CMDRStormBorn]

I simply cast old wheel weights into 10mm rounds for my glock 20.  I pity the large teddy I spray based on how they explode hardwood Trees I shoot with them.  You have to remember the sheer weight and magnum power of the mighty 10mm.  I remember back in the day when LEO and federal organizations moved away from the caliber to the weaker .40 cal due to so many cases of over penetration. Um, bear down on aisle 4 anyone?