.40 Short and Weak

[Hunter]

After the ballistic test I posted sometime back and the review of the Kahr CT 40 is over I am no so against the round as I used to be.
Opinions, thoughts?

[Raggedyman]

Macho interwebz commandos love to proclaim that the FBI ditched the 10mm in favor of the .40 S&W because the 10mm was just too awesome for their girly agents. The truth is slightly more complicated and far less dramatic. The velocity gained with the 10mm doesn't translate to better wounding in human targets but does translate to greater recoil. Greater recoil means slower shooting, no matter who you are. This is the part where interwebz commandos proclaim how inhumanly fast they are with THEIR sooper deathblastomatic in 10mm. Fine, but no matter how fast you are with 10mm, YOU would be faster with less recoil. More holes of the same size stops fights more quickly. For a defensive pistol that is purely for defense against human beings at ranges of 50 yards or less, the .40 S&W is certainly better. Even more so for a concealed carry handgun.

10mm can do things that .40 S&W can't, though. It is extremely versatile and can cover a very wide range of tasks. For one thing, the higher velocity means less drop, which would be useful if you anticipated a need to defend yourself at greater than 50 yards. Okay, that's not very likely but the flatter trajectory and greater downrange energy is useful for hunting. 10mm can also launch longer projectiles than the .40 S&W can and it can do it at reasonable velocity. That makes it useful for animal defense, though a big bore magnum is a better choice for large bears. An often overlooked feature of the 10mm is also a weakness. Because it drives bullets so fast, the velocity often exceeds the design parameters of bullets that were intended for .40 S&W. On the other hand, the extra velocity can coax expansion from cheap, old, cup & core style JHPs, even after passing through clothing. I don't know how practical that is as a feature but it's there. The extra velocity can also help to flatten the meplat of a heavy lead solid to get extremely deep (like measured in FEET deep) penetration while still cutting a respectable wound channel.

[The_Shadow]

I agree the 40S&W is what it is, and yes the bullets are geared more toward the ballistics it brings to the party.  Most of the newer guns chambered for the 40S&W, are lighter and shorter than the heavy weights made to replace the 10mm back in the day.  There were quite a few less polymer guns back then.  Therefore, I see where the snappy recoil is a tradeoff with these shorter lighter pistols and the velocity losses because the shorter barrels.  Yes they still perform a good role as a defensive pistol in close quarters.  While we 10mm guys poke fun with all the monikers we've hung on the cartridge over the years, it is a great cartridge.

I shoot many 40S&W cartridges from my 10mm pistols with conversion barrels, this has been beneficial in several ways; more practice using the same grip, feel, pointing, trigger and sight picture to maintain proficiency.  Being a slightly lighter loading, there is less wear on the pistol and the 10mm chambered barrel.  But the biggest plus has to be the abundance of 40 brass, begging for handloading with my cast bullets, for all the above reasons and to lessen the wear and loss of the 10mm brass while getting to play! 

[gandog56]

For one thing, the higher velocity means less drop, which would be useful if you anticipated a need to defend yourself at greater than 50 yards.

Actually there is no decrease in drop with equal bullet weight. They both drop at the exact same rate. It's just with the 10mm's higher velocity, it goes further horizontally during the same vertical drop interval. Which means it acts like the drop time is less, but it really isn't. Or to explain it even better....

Bullet drop is defined as the vertical distance of the projectile below the line of departure from the bore. Even when the line of departure is tilted upward or downward, bullet drop is still defined as the distance between the bullet and the line of departure at any point along the trajectory. Bullet drop is therefore of little practical use to shooters because it does not describe the actual trajectory of the bullet and is independent of the direction or distance to a target.

[4949shooter]

Let's not forget the medium velocity 10mm loads which exceed .40 S&W ballistics by 100 feet per second or so.

Would anybody take a 155 grain XTP or Gold Dot at 1280 to 1300 fps for self defense purposes? Not too much recoil or blast, but more speed than a .40 in that weight.

How about a 165 grain bullet at 1250 to 1300? Since most .40 loads in that weight are doing 1150, this is a nice increase in speed and kinetic energy without breaking the bank in recoil, muzzle blast, and wear and tear on your weapon. And if you consider the fact that the 165 in .40 is performing very well on the street, the extra 100 feet per second will presumably do even better.

It's a win - win in my opinion.

[radiotom]

From the gel tests I've seen, it seems like the 10mm has greater permanent cavitation at the beginning of the wound track than the .40. I've also seen this much more dramatically in my wet books testing.

EDIT: Not to mention the expanded slugs pulled from 10mm gel tests have often had an added .2 inches in diameter over the equivalent .40 loading. I'm looking at you, Gold Dots. Some of them almost expanded to an inch, show me a .40 that does that.

[ShadeTreeVTX]

The versatility of the 10mm from the Short and weak velocitys to the low end 41mag velocitys is a fact no one can deny.  Your contention that the 10mm does not do that much more than a 40 Seems to show me you don't really know the full usage the 10mm presents. The 40 is an all or nothing caliber - pick any bullet size and the 10mm destroys the 40, it can match or completely destroy the 40. The 40 to me is nothing but a hyper 9mm, which the 357sig beat easily and holds the 40 off and exceeds it in allot of other areas. The big is better ( 180 to 220 grain heads) only works in the 10mm. If the 40 is so great, why do they keep trying to match the 10 - kinda like penis envy if you ask me. Just remember the 40 is the little brother and 10mm is big brother and still the baddest.
The 10mm demise is recoil, if you can't handle it don't play in the in the big sand box -
Why settle for less than the best.
A person has to know his limitations and abilities, the crying towels are handed out at the exit door.

Doug

[Rojo27]

The velocity gained with the 10mm doesn't translate to better wounding in human targets but does translate to greater recoil. Greater recoil means slower shooting, no matter who you are............Fine, but no matter how fast you are with 10mm, YOU would be faster with less recoil. More holes of the same size stops fights more quickly. For a defensive pistol that is purely for defense against human beings at ranges of 50 yards or less, the .40 S&W is certainly better. Even more so for a concealed carry handgun.

While I'm still new to this forum; I've been a long time admirer of the 10mm because of the versatility you fairly pointed out.  However, I don't subscribe to 1 caliber sidearm is always best alternative for every occasion either.
With that stipulated and with all due respect; I haven't found much empirical real world data to support the initial declarative statement regarding 10mm wounding in humans.   
May also be relevant to point out, development of .40 had as much to do with shorter case permitting utilization in smaller 9mm frame pistols of 1980's vintage vs. full size .45acp size frames then in use (see Bren Ten).
With regard to "faster" with "more holes" elements.  Not saying I necessarily disagree but wonder if that logic at some point starts to support what the 9mm (similar size holes) fans been saying all these years? 
If Wikipedia is accurate:
"Despite the F.B.I. switching to the .40 S&W, their Hostage Rescue Team, Special Weapons and Tactics Teams, and various other law enforcement agencies in the United States still continue to issue or authorize the use of 10mm."
On a final note.  Got nothing against .40, 9mm, 357sig, (45acp in night stand right now) they can all be very effective with reams of empirical data to back it up.  Depending on occasion/situation any one of them may get the nod.  However, when the occasion calls for full size these days; personally very satisfied with 15+1 of ballistics superior to 357 magnum on tap.

[Raggedyman]

For one thing, the higher velocity means less drop, which would be useful if you anticipated a need to defend yourself at greater than 50 yards.

Actually there is no decrease in drop with equal bullet weight. They both drop at the exact same rate. It's just with the 10mm's higher velocity, it goes further horizontally during the same vertical drop interval. Which means it acts like the drop time is less, but it really isn't. Or to explain it even better....

I get that. Even bullets of dissimilar weight will fall nearly the same distance in a given period of time in atmosphere because the acceleration rate of 32 ft/sec^2 is a constant on Earth. As I used it, "less drop" refers to fewer inches between POA and POI on paper. In practical terms, it means a greater chance to hit your target at extended ranges, perhaps I should have used different phrasing. Holdover is difficult with iron sighted pistols.

[Raggedyman]

Let's not forget the medium velocity 10mm loads which exceed .40 S&W ballistics by 100 feet per second or so.

Would anybody take a 155 grain XTP or Gold Dot at 1280 to 1300 fps for self defense purposes? Not too much recoil or blast, but more speed than a .40 in that weight.

How about a 165 grain bullet at 1250 to 1300? Since most .40 loads in that weight are doing 1150, this is a nice increase in speed and kinetic energy without breaking the bank in recoil, muzzle blast, and wear and tear on your weapon. And if you consider the fact that the 165 in .40 is performing very well on the street, the extra 100 feet per second will presumably do even better.

It's a win - win in my opinion.

Not exactly. There is very little difference in actual wounding between service pistol calibers. A hit with a 9mm has similar effect to a hit with a .45 ACP. There is nothing magical going on. A 165 gr Gold Dot moving 100 fps faster *might* theoretically cut a slightly wider wound channel but in practice that extra 100 fps has no impact on the time to incapacitation. While the extra recoil and blast might not be dramatic, there IS a difference and as I mentioned above, less recoil means faster shooting, which means more holes in bad guys, which means faster incapacitation.

[Raggedyman]

From the gel tests I've seen, it seems like the 10mm has greater permanent cavitation at the beginning of the wound track than the .40. I've also seen this much more dramatically in my wet books testing.

EDIT: Not to mention the expanded slugs pulled from 10mm gel tests have often had an added .2 inches in diameter over the equivalent .40 loading. I'm looking at you, Gold Dots. Some of them almost expanded to an inch, show me a .40 that does that.

You can't normally see the permanent (or "crush") cavity in gelatin or other gel tests. The diameter of the permanent cavity is measured by taking the average expanded diameter of the projectile (  (max expansion+min expansion)/2 ). Volume of the crush cavity is the result of multiplying the previous number by the length of the track.

What you are seeing in the gel is the temporary (or "stretch") cavity. This has no substantive effect on wounding at pistol velocities (<2,000 fps) but looks dramatic in gel. Human tissue (with the exception of brain and liver tissue) can stretch and return farther than gelatin can so the gel shows fractures. Those testers that have high frame rate cameras can often capture the temporary cavity at or near its widest point.

That said, 10mm expanded diameters are typically slightly larger than the same bullet in .40 S&W. Theoretically, that means a larger permanent cavity, but only by a slight margin and then we consider that .45 ACP expanded diameters are typically larger than a similar bullet in 10mm. I know most of you have seen this but it's probably time to take a look again:

[Raggedyman]

While I'm still new to this forum; I've been a long time admirer of the 10mm because of the versatility you fairly pointed out.  However, I don't subscribe to 1 caliber sidearm is always best alternative for every occasion either.
With that stipulated and with all due respect; I haven't found much empirical real world data to support the initial declarative statement regarding 10mm wounding in humans.   
May also be relevant to point out, development of .40 had as much to do with shorter case permitting utilization in smaller 9mm frame pistols of 1980's vintage vs. full size .45acp size frames then in use (see Bren Ten).
With regard to "faster" with "more holes" elements.  Not saying I necessarily disagree but wonder if that logic at some point starts to support what the 9mm (similar size holes) fans been saying all these years? 
If Wikipedia is accurate:
"Despite the F.B.I. switching to the .40 S&W, their Hostage Rescue Team, Special Weapons and Tactics Teams, and various other law enforcement agencies in the United States still continue to issue or authorize the use of 10mm."
On a final note.  Got nothing against .40, 9mm, 357sig, (45acp in night stand right now) they can all be very effective with reams of empirical data to back it up.  Depending on occasion/situation any one of them may get the nod.  However, when the occasion calls for full size these days; personally very satisfied with 15+1 of ballistics superior to 357 magnum on tap.

Please read http://www.firearmstactical.com/pdf/fbi-hwfe.pdf particularly page five in regards to temporary stretch cavity. Also refer to the image above.

[pacapcop]

 www.brasstard.com     2011 Review of G20 and wet pack phone book test's of real 10 loads and .40 cal. That sold me at the time. The Venerable Glock 20 article.

[Rojo27]

Please read http://www.firearmstactical.com/pdf/fbi-hwfe.pdf particularly page five in regards to temporary stretch cavity. Also refer to the image above.

Interesting study written by Special Agent but not exactly the empirical data I am looking for. 

Not to redirect but a similar argument could be made around actual quantifiable incapacitation results of 9mm & 357 magnum.  As far as diameter goes, almost identical.  What are we left with to explain the quantifiable differences in wounding results?  Mass and speed of the projectile; No?  In gel, I'll bet they'd look similar to others in the picture you posted but the actual results are clearly different.

[pacapcop]

Hence above reference.