What's wrong with .40S&W?

[farscott]

My only issue with .40 S&W relates to the pistol I use. I shoot .40 S&W in an STI Trojan 6.0, and it needs a long OAL for reliable functioning. The OAL is very close to 10mm, so I might as well shoot a 10mm. In fact, my Trojan is slated to be fit with a 10mm barrel.

 

[Island Beretta]

What's wrong with the .40S&W is that it is a solution to a non-existent problem. I know many shooters who rushed to get .40S&W due to the hype in the nineties and many have migrated back to 9mm or .45s.

Heck, if you want to talk about high energy with even better capacity and a round that manages the high pressures a lot better than .40S&W, then get the .38 Super.

 

[euclid]

Nothing. It's an awesome round.

cheers

 

[Clark]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.


JohnKSa and C-Note,
What I mean when I say: "The 40sw has more power potential than the 10mm with handloads and good case support", is that I have overloaded the 10mm and 40sw with good case support until the case fails and the primer falls out.

The 40sw can get more velocity with the same bullet.
With 200 gr bullets and "Hi-Skor" 800-X:
1) 10mm, max load 7.8gr 1130fps 32500 psi, overload: 14.2 gr, case bulge
2) 40sw, max load 6.3 gr, 925 fps, 26100 psi, overload: 15.5 gr, case full
3) 44 mag, max load 15.5 gr, 1600 fps, 39, 800 cup


What does it all mean?
The 10mm primer pocket is too big for the size of the case, so the 40sw passes it up.

 

[JMag]

Island Beretta has it pegged...

 

[GOT]

I know many shooters who rushed to get .40S&W due to the hype in the nineties and many have migrated back to 9mm or .45s.

...and they have begun to see past the S&W .40 hype and realize the awesome potential of the 10mm.

 

[Clark]

Got,
Per my experiments, the 10mm has less potential than the 40sw... unless you found a source for small primer 10mm brass.

 

[GOT]

Per my experiments, the 10mm has less potential than the 40sw...

That is utter nonsense. The useful case capacity is of the .40 is 0.69cc and 0.95cc for the
10mm. The case is bigger.

Clark, have you shot either the .40 or the 10mm? How about reloaded? I haven't reloaded but I have Hornady's 5th edition reload manuals and its quite clear that the 10mm has a LOT MORE potential than the .40.

Look at the image. Thats a .40 on the left and a 10mm case on the right.

 

[farscott]

If I understand Clark, his reasoning is that the .40 S&W brass, independent of the firearm used, is superior because it can withstand higher pressures even though it has a smaller capacity. .40 S&W brass appears to be stronger due to the use of the small primer versus the large primer of the 10mm Auto, and the .40 S&W brass is thicker in the case head area adjacent to the primer flash hole than 10mm Auto brass. His reasoning appears to be sound and is an analogue to the design of the .454 Casull and 9x23 Winchester, both of which use small rifle primers to produce and withstand higher pressures.

If the .40 S&W brass allows higher pressures than the 10mm brass, it may be possible that the higher pressure offsets the larger capacity advantage of the 10mm brass for some bullet weights, especially lighter ones. Obviously, 10mm Auto brass strength could be improved by adopting the smaller primer of the .40 S&W. Of course, this all is moot without pistols or handguns capable of handling the increased pressures.

 

[Clark]

Farscott,
Per my experiments:
1) The only pistol I have tested that cannot take more pressure than the brass, is the CZ52, due to it's thin chamber bottom.
2) Revolvers often split the cylinder and break the top strap before the brass flows.
3) The real limit I find for pistols [CZ52 excepted] is:
a) case support
b) case design
c) recoil
d) primer piercing
e) case full

What I mean by case support is the feed ramp intrusion into the chamber. If this is forward of the web, there is thin unsupported case wall that can blow a hole.

What I mean by case design can be seen in GOT's pictures, the wall around the primer pocket of a 10mm case is thin.

What I mean by recoil limiting power, is that the momentum of bullet and gas is largely absorbed by slide velocity. That velocity is stopped by the recoil spring. If the powder charge is increased, the spring force must be increased. If the spring force is increased enough, the average man cannot pull back the slide and the average magazine spring cannot push up another round as fast as the recoil spring can accelerate the slide forward.

What I mean by primer piercing is that at high pressure, the firing pin can make a hole in a primer. This can be overcome slightly with going to a magnum primer that is thicker brass. Some pistols cannot fire magnum primers without increasing the strike force.

What I mean by the case is full, is that no more powder will fit. Even with double compression, there are very few powders with the density - speed product to reach case failure or primer failure in 25 acp, 32acp, .380, 9mm, etc. Most people think of Bullseye, but it is way down the list. AA#5 is tops, with 3N37 and HS-6 having high products too.

--
A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.

 

[cxm]

My objection to the .40?

Can you say Kboom!!!!!

/r

Chuck

 

[NavajoNPaleFace]

Simply put I would much more hate to be on the receiving end of a .40 in the hands of someone able to shoot it.

In short...find a gun you can hit with....be it it a .22, .32, 9MM, .40 or .45ACP. It's far better than one that you have that you can't hit didly.

 

[Hal]

Can you say Kboom!!!!!

yep - sure can
setback is how I pronounce it though.

Somewhere on the net are pressure figures for the .40S&W vs bullet seating depth using a 180 gr bullet. I'm too lazy to look them up anymore.
Bottom line is with very minimal setback into the case, the .40S&W 180 gr loads go off the pressure scale big time.

The only other loading I'd personally feel warm and fuzzy about in the .40 would be the 165 gr load, which doesn't appear to suffer the same ill effects as it's heavier brother load.

I'm sorry, but 165 gr in a .40 in bore doesn't have the sectional density I desire. I consider it just marginal @ .147. Not all that bad, but it could be better.

180 gr OTOH is >.16. that compares very well with a .230 gr .45 slug., and it's neighborhood close to a 158 gr .357 @ .17. But there's that old setback/pressure issue again.

Try as I might I can't see an advantage to the .40 over the .45acp.

RE. .40 S&W being "A hell of a lot cheaper to reload".
How so? Doesn't add up.

 

[farscott]

Clark,

Your results are interesting and thought-provoking. I may have to reassess my thinking about the .40 S&W. I was planning on adding a 10mm barrel to my Trojan 6.0, so that I could use it as a hunting handgun. I may be able to save some money and use it for load development. Thanks for the information.

When I mentioned "handling the increased pressures", I was thinking of an unsupported section of case failing. I think some of your other limits, depending upon pistol design, may be mitigated. For example, an unradiused firing pin stop on a 1911 may be used to delay unlocking and reduce slide velocity. This would allow a lighter rate recoil spring, so the recoil limit may be increased. Primer piercing may be eliminated by the use of small rifle primers. Case full, of course, is a hard limit unless a case is lengthened.

Lots of stuff to ponder.

 

[Clark]

Farscott,
To shoot those 44 mag loads in a 40sw, I needed much better case support than a stock Glock 22 barrel. The usual procedure is to get a Barsto or other after market barrel.

I had the feed ramp TIG welded up and re-cut the feed ramp and chamber so the case is supported all the way back to the web.

It depends on what you want to do with the 40sw.
1) If you want to arm a police force of partly tiny women, a stock Glock 22 might be good with factory 40sw ammo.
2) If you want to hunt, maybe a large framed pistol with long barrel and heavy slide, like a Glock 20 with 40sw barrel or 1911 with 40sw barrel. Either pistol will allow longer over all lengths than I used above. Don't think that the 44 mag 200 gr. loads in a 40sw will only do 1600 fps. The peak pressure is much higher, and so is the velocity.
3) For concealed carry, a Kel-Tec P40 or Kahr Covert plastic KPS4043A.
These tiny pistols can be modified to take high pressure handloads, but the recoil is not compatible with human hands for the extreme loads I have described above.

 

[wally]

180 gr OTOH is >.16. that compares very well with a .230 gr .45 slug., and it's neighborhood close to a 158 gr .357 @ .17. But there's that old setback/pressure issue again.

Try as I might I can't see an advantage to the .40 over the .45acp.

You are on the right track. At equivalent barrel length the .40 S&W will have about 100 fps more velocity for better penetration than .45ACP. In smal CCW I see a plus for .40 S&W so I might stay with my Kahr PM40 even if they came out with a PM45 of the same size, as the .40S&W would have better penetration.

Niche caliber for me, but I like it.

--wally.

 

[Daniel L]

Even H&Ks USP full size holds 12 rounds of .45, 13 rounds of .40, and 15 rounds of 9mm. The increase in energy and decrease in capacity is nearly perfectly linear from 9mm to .40 to .45.

As was said earlier, in the right gun, it's a great round. Compare the full size to the compact. The USP Compact holds 8 in .45, 12 in .40, and 13 in 9mm.