Good all in one Black Bear to Deer in a factory 10mm?

[Roguer]

The Dumb OP said Glock 40. 

[Rojo27]

The Dumb OP said Glock 40. 

My bad, apologies.

[Overkill338]

Those Xtreme Snakeoil pills just dont cut the mustard. OP, the hardest will out penetrate the "Xtreme (Under)Penetrators" 3:1. Not to mention, the weight comparison is like car crashes. If you were getting T-Boned at a 4 way intersection, would your rather be hit by a Sportbike going 100 mph or a Semi with trailer running 50 mph ?

The hyperbole and false equivalency aside.  A good 200gr to 220gr Hard Cast will certainly out penetrate the Underwood Xtreme lines but the 3:1 ratio business is provably inaccurate.  This question has been conclusively resolved by member(s) here and the information is easy to find on this forum.  Not that it matters in the slightest with respect to the original question posed by the OP.   

The OP was asking for a single factory recommendation for two specific jobs (medium sized game hunting & Black Bear defense).  There are any number of factory offerings in 10mm which will do an excellent job in those two jobs (Hard cast & Xtreme lines certainly among them).  Lots of excellent ammunition options in 10mm that'll make a deer or black bear very dead if the shooter does his or her part and puts them where they need to go.  The great thing is the ammo choice list gets bigger all the time.

Not sure if the Glock 40 factory barrel had the same problems as Glock 20 factory barrel with 220gr Underwood Hard Cast and it's tendency to not destabilize the projectile which often allowed bullet to keyhole. Not that great an outcome for either job OP seeking a solution for.  At any rate Glock itself advises against shooting hard cast in their polygonal rifled barrels.   

The 3:1 was just overstating my point with a bit of sarcasm. Most of the folks that have already spent money on the xtreme this and that will defend them to the death. They will fade away though.

Rojo, I'm curious as well about if the 220 will stabilize in a G40. I would think it's more about twist rate than barrel length, wouldnt you?

[Rojo27]

Rojo, I'm curious as well about if the 220 will stabilize in a G40. I would think it's more about twist rate than barrel length, wouldnt you?

Hey Overkill,
I honestly don't know if the barrel length of the G40 helps it stabilize the hardcast better than G20 or not.  The twist rate would logically make sense but I don't know what that is in G20 vs. G40 or any of the other pistols that seem to be able to stabilize the heaviest hardcast bullets.  The polygonal rifling that Glock uses could also be the culprit.  I'll defer to others here more informed than I on the physics of internal & external ballistics. 

[Overkill338]

Rojo, I'm curious as well about if the 220 will stabilize in a G40. I would think it's more about twist rate than barrel length, wouldnt you?

Hey Overkill,
I honestly don't know if the barrel length of the G40 helps it stabilize the hardcast better than G20 or not.  The twist rate would logically make sense but I don't know what that is in G20 vs. G40 or any of the other pistols that seem to be able to stabilize the heaviest hardcast bullets.  The polygonal rifling that Glock uses could also be the culprit.  I'll defer to others here more informed than I on the physics of internal & external ballistics.

Stock Glock 20 and 29 barrels are 1 in 9.84". So I guess it is the length.

[sqlbullet]

Actually, it would be the extra velocity the length imparts.

[Graybeard]

Length, twist rate and speed are all factors. Assuming the same twist rate, a barrel half as long only rotates the bullet half as much over (roughly) half the time. The rotational force ends when the bullet exits the barrel.

It's illustrated well in .38s. A .38 snubbie may struggle to stabilize 158gr bullets and a 6" .38 may shoot them like a tack driver. Both may work great with 125s.

Sqlbullet isn't wrong, though. Traveling faster through the same twist increases the revolutions as the time factor is decreased. There is a point of diminishing return there if you run out of barrel to impart that spin.

[Muskrat]

Since black bear attacks are fantastically uncommon, and black bears are not particularly hard to kill, I'd recommend the OP concentrate on whatever cartridge they think will work best for deer. Whatever that is will be MORE than enough to deal with any bear issue.

If it's accurate out of the OP's gun, I'd look no further than the Federal Trophy Bonded 180 grain.

[Rojo27]

Actually, it would be the extra velocity the length imparts.

So a 4.6" Glock has issues with the 220gr hardcast but similar barrel length 10mm like the Tanfolio don't? 

Hadn't heard same issue plaguing 5" 1911 pistols.  Does it?

[50BMG]

Thanks people!

One of my main reasons for getting my 10mm besides wanting one for ever and ever and ever and ever, was for deer hunting and feral dogs. The later are the main problem that has only been some what controlled with the local wolf population rise.  Another thing that I saw last deer season was cougar that the DNR says don't exist that was in the old farm yard area, it looked BIG but healthy so it probably should be no worry.

You sound like you are in MI. Rouger. I have a DNR friend who for a long time would privately admit the cougars were in MI., but publicly the DNR STILL won't make those confirmations it seems....
if it walks like a duck...

[Graybeard]

  MI resident myself. Always got a chuckle out of the DNR's position on this. Dead deer parts and cougar tracks on the Lake Superior shoreline and lots of sightings for the last 20 years = nothing to see here people. Just misidentification caused by big house cats..........

[sqlbullet]

Lots of state DNR's don't acknowledge the presence of certain non-native species.  It is for political and budgetary reasons.  If they acknowledge the cats presence officially, then they are legally required to produce documentation and planning for how to manage the species.  That can be a very large monetary and workload burden on an already under-funded department.  So, as a result, they have policies that allow them to not list a species until certain thresholds are met.

[Graybeard]

Almost all of the valid cougar sightings in MI are in the upper peninsula. The economy there is heavily tourist dependent. They won't acknowledge cougars there until one eats somebody. They don't want to scare off anyone from spending their money up there and they don't want to draw any ill intentioned people who may want to shoot one. Our DNR, while they don't acknowledge their existence officially, have made it know many times that it is illegal to shoot them.......

In the last ten years we've had some other interesting non native cats loose in southeastern MI At least one leopard and a tiger that was running around the Detroit suburbs.

[sqlbullet]

Length, twist rate and speed are all factors. Assuming the same twist rate, a barrel half as long only rotates the bullet half as much over (roughly) half the time. The rotational force ends when the bullet exits the barrel.

It's illustrated well in .38s. A .38 snubbie may struggle to stabilize 158gr bullets and a 6" .38 may shoot them like a tack driver. Both may work great with 125s.

Sqlbullet isn't wrong, though. Traveling faster through the same twist increases the revolutions as the time factor is decreased. There is a point of diminishing return there if you run out of barrel to impart that spin.

So a 4.6" Glock has issues with the 220gr hardcast but similar barrel length 10mm like the Tanfolio don't? 

Hadn't heard same issue plaguing 5" 1911 pistols.  Does it?

Bullets stabilize based on their length and diameter when using the classic Greenhill formula.

twist = 150*(projectile diameter^2/projectile length)

But, this simplistic formula assumes a lead bullet traveling at velocity around 1900 fps.

In all reality we are looking for gyroscopic stabilization, which is determined by the spin rate (revolutions/time), projectile geometry, projectile density.  Given the modern complexity of bullet shapes and composition, we are lucky that averages of these last to attributes work just fine for the most part.

The Bowman equation extended Greenhill to account for the impact of velocity on spin rate.  Increase velocity (distance/time) for a given twist (revolutions/distance) and the spin rate goes up, increasing stability.  This equation assumes that velocity is in inches per second:

twist = (sqrt(velocity)) * (projectile diameter^2/projectile length)

However, since we usually measure velocity in feet per second, and the square root of 12 is 3.4641, Bowman's equation is usually simplified to:

twist = 3.5 * sqrt(velocityFPS) * (projectile diameter^2/projectile length)

As different materials are used in bullet construction, the specific gravity (SG) of the bullet changes, usually going down since very few elements available to reloaders are more dense than lead.   As SG goes down, the bullet has to spin faster to compensate.  Different shapes also impact this as long boat tail hollow point bullets are longer than their mass would suggest, but in general these factors do not play heavily into handgun bullets.

Barrel length has no bearing on stabilization except as it impacts velocity.  Increasing barrel length usually increases velocity and therefore spin rate, allowing bullets to better stabilize.  But this really only applies if you have a bullet the is barely stabilized.  In general twist rates are faster than needed because there is a big delta between the minimum spin rate to stabilize and the maximum spin rate before the bullet rips itself apart. (Although that can happen if you shoot super-light varmint bullets out of a fast twist barrel meant for heavy, long range target bullets.  Think 36 grain .224 bullets out of a 22-250 in a 1:7 twist barrel meant for 90 grain bullets.)

Increasing barrel length does not impact twist rate.  A bullet fired from a 1" barrel and a 30" barrel in a 1:16 twist will both rotate 1 full revolution for every 16" of travel.  The rifling does not accelerate the spin the longer the bullet is in the barrel.  Unless it is gain twist rifling or the bullet is skidding in the rifling.

When talking about 10mm and doing the math assuming a 200 grain bullet of about .625" of length, any twist faster than 1:20 should be more than fine for any velocity above 600 fps. 

So, we are left with the mystery of why a longer barrel on a Glock seems to make a difference but the same bullet stabilizes fine in other guns with similar length barrels.  On the face of it, the Glock's faster twist should provide for success with even shorter barrels and corresponding velocity and spin rate reductions.

I personally think three factors are at play here and I think they are resulting in some bullet skid in the rifling.

Factor one is the ridiculously fast twist in the Glock barrel.  1:16 is pretty standard for pistols in 9mm and larger.  As we have said, 1:20 is fast enough for even the most anemic 10mm loads in long bullets, and shorter bullets require less spin to stabilize. So, the Glock spin is more than twice as fast as needed, and more than three times as fast as needed at 10mm velocities (1:31 at 1200 fps)

Factor two is the loose Glock groove diameter.  Every Glock I am aware has slugged at .402" give or take.  I have not measured bore diameter, but the excess groove diameter provides some slop.

Factor three is the polygonal rifling that Glock uses.  This results in less abrupt, sharp, grabby rifling.

I think these three factors together allow the bullets a significant amount of skid that you don't see in a 1:16 cut rifled barrel.  As a result, spin is not being fully imparted to the bullet at the time of engraving, and the bullet behaves more like it is being fired from a gain twist barrel

my 2¢

And some citations:

Here are some twist calclulators.  Note that none of them ask for barrel length.

http://bergerbullets.com/twist-rate-calculator/
https://thebarreloutlet.com/twist-calculator/
https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

And finally, another calculator with sources and additional info about Greenhill Bowman and others twist formulas:

http://kwk.us/twist.html

[Roguer]

MI resident myself. Always got a chuckle out of the DNR's position on this. Dead deer parts and cougar tracks on the Lake Superior shoreline and lots of sightings for the last 20 years = nothing to see here people. Just misidentification caused by big house cats..........

Nope. MN. 

I found my old stash of 10mm DT 200 grain HC Lead solids. I'll have to see if there is a feeding issue with my LWD barrels for it. It appears the feed ramps might be to small for the broad bullet flat nose from what I Googled-Fued. Since we are going to have some cold weather the 416R LWD barrel will be going in it for the lead ones.  When I had money I invested in a few "On sale LWD barrels" seems my idea was a good one, even got one with a comp. They make the same type of barrels under double diamond brand of the LWD ones I have, not the Alpha Wolf ones.

Good added info I see. Very informative.