.45ACP is great in mid to full size guns. Is it so great in really short/small guns?

IMHO, I think the .45ACP is just fine even if moving slower out of a short barrel. It is still a big, fat bullet that will make a nice hole, expansion or no expansion. I am one of those oddballs who think .45 FMJ at whatever velocity will serve you just fine if you place it right.

It depends on what camp you belong to. The light and fast camp or the big and slow camp. Lately many of the light and fast camp have been coming over to the .45 and demanding big and fast. This works pretty well with 5" .45's with standard rifing. Put the same standard on a 3" .45 and suddenly the big and fast no longer works.
Luckly the .45 is already big enough to not have to depend on hollowpoint or expanding bullet technology to be effective. As we all know .45 FMJ will get the job done. Around the turn of century the British officers carried .455 revolvers that did not have much better ballistics than a modern 4 inch .45 and no one complained about thier ability to handle the job.
I tend to choose shorter barrel .45's with polygonal barrels as they give a better seal and squeeze a few more FPS out of the .45 ACP round. Then I look at bullets designed to function at the velocity that these short barrels put out.
That said, I would not carry a .45 with under a 4" barrel by choice.

Its Known for its stopping power HP or not But...

The .45 ACP is known to loose a substantial amount of velocity as the barrel gets shorter. So I would think the energy and penetration would suffer greatly also (and of course its potency). The 9mm and .357 mag doesn't have this trait, I prefer them in short barrel guns but with good ammo (they are small so their effectiveness depends on ammo design) . Guns and Ammo, IIRC did a test on this subject some years ago.
With the advancement on modern bullet technology we have now, It probably can be made effective (light HP bullets?) in short barrel, but its now going to be ammo dependent just like the rest. Its going to loose its most desirable trait if you go shorter than 4 inch barrel, IMO.

So ya'll are telling me that taking a slug from a 3" barrel in .45 will not kill?

Good question.

For optimum performance, the bullet must be traveling at the "right" speed. Barrel length's got a lot to do with that as does the pressure, which is dependent on the powder and how much of it there is.

My guess is that the .45 would take third place in a short barrel contest with standard rounds.

According to a gun rag from a couple of years back, going from a 5" to a 3.16 (Kimber) barrel results in about a 125 fps loss of velocity (variable depending brand and model of ammo). In other words, a comparable loss as shooting a target further than 50 yards away with a 5" barrel.

Longbow, can you cite a source for your statement that the 45 ACP loses more velocity with a short barrel than the 9mm and 357 Magnums do?

Even with this loss of velocity, I'd be willing to bet that a 230 Gr .45 caliber projectile at 700 fps would penetrate significantly into a human torso. Furthermore, one of the attractions of the choice of .45 over 9mm is that the 9mm crowd tends to rely on expansion. All things being equal, a larger hole will stop most targets than a smaller hole. If there is no expansion, then you are left with penetration. 9mm 147 Gr will probably have 'adequate' penetration as will a 158 Gr 38 slug. But so should a 230 Gr 45 ACP projectile. It just depends on how big of a hole you want to leave. I'll still take the 45.

Plus, unless were talking purely in the theoretical realm, you have to look at what's available. Most small 45s have a 3.5" barrel, not a 2" like some 38 Specials. I would rather have an Officer model than a snub nose 38.

And by the way, JMB might have opted for a .355 caliber in a full size gun. My guess is JMB would opt for a shotgun.

He was smart and that's what a smart person would opt for, if available.

Cratz2,
As I have said, IIRC its in Guns and Ammo some years back.
As for stopping power, I belong to the shot placement camp. Any caliber mentioned on this thread is capable of stopping someone so long that it hit a vital organ/area of the body. Choice is purely individual, its your call! Cheers!
P.S.
I prefer my guns in .45 ACP's in 5 inch barrel nothing less.

If you just gotta have a .45, then certainly you're not using a slingshot with a 3" barrel... But if you're open to other options, you MIGHT get better performance from a smaller, higher velocity caliber.

Look at it this way... the .45 is of course designed around a 5" barrel. The .40 was designed to be launched from a 4" barrel, so going to a 3" barrel is not as significant a deviation from optimum as the .45.

Either way, I'm not volunteering to hold your target for you I'm allergic to pain!

45 in a tiny gun with a 3" barrel

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I resemble that remark!!
My carry pistol is a Glock 36. It fits in my pocket, ankle, strong side... need I say more???

185gr bullets work just fine in it!!!

My carry pistol is a Glock 36.

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For some reason, testing has shown the "little" Glock .45's to suffer less velocity loss with standard pressure loads than other short-barrelled .45...

This data is for the Glock 30, but I can't imagine why the 36 would be much different.

http://greent.com/40Page/ammo/45/45velocity.htm

But then again, this is comparing a 4.60" barrel to a 3.78" barrel as opposed to 3" and 5".

The Glock's barrel design allows for higher velocity. Most Glock's I've chronoed produced more velocity compared to other pistol of similar caliber and barrel lenght. It's design is really phenominal, IMO. Needless to say, I like Glock's.

I read somewhere, and I can't tell you where and I would not swear to it, but best as I recall, 9mm ammo was essentially designed for 4" barrels. Maybe I assumed this to be the case as that is what Bob Forker used as the standard length barrel for doing gathering ballistics data at various distances in his "Ammo and Ballistics" book. The early Lugers had 89 mm (3.5") barrels as a standard and then several variations (as I recall from some other reading).

SO, the assumption that rounds such as the 9 mm do better from 4" and 3" barrels as compared to .45 would quite possibly be true. Why? The .45 acp was designed to reach the required velocity of 850 fps for a 230 gr. slug out of a 5" barrel and to be able to cycle the 1911's slide that is of a certain mass. So, powder type and quantity was for that specification. Going to a shorter barrel means the bullet does not have as much time to get up to speed. The difference between velocity loss with a 4" barrel compared to a 5" is less than the amount of loss in a 3" barrel. Being 2" shorter, the 3" barrel loses more than double the loss experienced by the 4" barrel. In other words, the more you move down from the designed norm, the velocity loss is not linear, but curvilinear.

Something to point out here is that JMB's 1911 design coincided with the .45 acp cartridge design. They were made for one another. JMB apparently did not invent the Commander or Officer's models of 1911s. Most Commanders with a 4.25" barrel are close enough to the specs of a 5" 1911 so as to still work reliably. Part of the key here is slide mass. One you get down to the officer's size 1911, the much lighter slide is not close to the original 1911 mass and so the slide tends to cycle to fast (without enough dwell time to eject the spent case and pick up a new round and feed it into the chamber. For both Commanders and Officer's guns, one way to help assure that the gun will have enough dwell time is to have a heavier spring than is used on the full-sized 1911. Especially for the officer's guns, finding that perfect spring to compensate for the lighter slide has tended to be less than optimal in most cases for reliability. My guess is that had JMB needed to design a 1911 with a shorter barrel and still reach the same 850 fps velocity, then he would have used a faster powder to bring the slug up to speed quicker and probably would have needed to design the barrel to handle the greater pressure that would be needed get the slug up to speed quicker.

So, the idea that 9 mm does better in 3 or 4" barrels may be true simply because these lengths are close to the design specs. The round is meant to be up to speed at about those distances.

I have fired two compact or small .45s: the Republic Arms Patriot (DAO, 20 oz) and the Star PD (25 oz). I find the recoil from these guns rather unpleasant. If you want to shoot .45s a good bit, I think it is best to stick to larger autos, say, those which weigh 30 oz or more. Ditto 9mm pistols weighing less than 27 or 30 oz.

Drakejake

Something to point out here is that JMB's 1911 design coincided with the .45 acp cartridge design. They were made for one another.

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Actually, 98% of the design that went into the 1911 was designed around a cartridge similar to the 38 Super, not the 45 ACP. He was basically done with the design when the Army decided, almost haphazardly on a .45 caliber bullet.

Call me niave, or call me hard headed but I just can't see how a round that largely depends on expansion and high velocities can be as effective from short barrels as a round that needs no expansion at all. I am a die hard 45 guy and 1911 guy. I admit that. But a half inch hole through somebody is still a half inch hole through somebody. Expanding 9mm ammo is designed to expand and not completely penetrate a person from a reasonable angle. I'm not suggesting that a standard pressure 230 Gr .45 ACP slug will expand reliably when launched from a 3" barrel, I'm saying that a 230 Gr FMJ slug will pretty reliably completely penetrate a human male torso with regularity with a straight on angle shot whether it comes from a 3", 4" or 5" barrel.

Now if we get into the subject of wound-induced shok and temporary wound cavaties and one shot stop percentages being higher with high velocity, expanding ammo, then that is another subject. I'm just asserting that an Officer model 1911 will consistantly shoot through a person, pretty reliably, depending on what clothes are being worn.

I will agree with Longbow on shot placement. And it is true that a 147 Gr 9mm probably offers better penetration than a 230 Gr 45 ACP. Oh well, the gun you have when you need it is better than the full size 1911 loaded with Gold Dots that you left at home.

Did I misunderstand somewhere? I thought the traditional officer's model guns had 3.5" barrels while the Commanders had 4.25" barrels.

Cratz2, the early prototypes of 1911-like guns may have been in other calibers, no doubt. Heck, you can see features common to the 1911 in guns like the 1903 even. The original gun submitted by Browning in 1905 in caliber .45 acp is really significantly different than the gun that turned out to be the 1911...having gone through numerous morphs and design changes. The earlier .38 or .38 Super guns may have been like the 1905.