relationship between military pistol and rifle cartridges

[TonyDedo]

I was talking with some friends about my firearms, and we were discussing the difference between modern US military cartridges (9mm and 5.56) and historical (.45ACP and .30-06). Looking at the four cartridges next to each other, it dawned on me that the pistol and rifle casing from each generation have nearly the same diameter. In order words, the diameter of a 5.56 cartridge is (or nearly is) the same as the 9mm, and the .45 seems to have the same diameter as the .30-06. Is this by design? Is the brass from a pistol cartridge just a trimmed down version of a rifle cartridge? Is this part of a war time manufacturing technique?

Obviously this isn’t a vital question, just a curious question that came up.

 

[Pilgrim]

delete - I don't know what I'm talking about.

 

[Finalygotabeltfed]

I was talking with some friends about my firearms, and we were discussing the difference between modern US military cartridges (9mm and 5.56) and historical (.45ACP and .30-06). Looking at the four cartridges next to each other, it dawned on me that the pistol and rifle casing from each generation have nearly the same diameter. In order words, the diameter of a 5.56 cartridge is (or nearly is) the same as the 9mm, and the .45 seems to have the same diameter as the .30-06. Is this by design? Is the brass from a pistol cartridge just a trimmed down version of a rifle cartridge? Is this part of a war time manufacturing technique?

Obviously this isn’t a vital question, just a curious question that came up.

They are close, but not exact. The wall thickness of the .308 and 30.06 rifle cartridges are thicker than that of the .45acp and they are also tapered. The walls of the .45acp are straight and thin.
I have worked with a friend making .45 blanks from cut down 30.06 rifle cases and a star crimp. For blanks, they work fine....for loading bullets, the inside of the case would have to be reamed to accomodate a .451 diameter .45acp bullet.

In a pinch, YES you could make .45acp ammo from .308 and 30.06 rifle case....but have your micrometer and a reamer ready.

Looking at the dates of development of the various cartridges, 9mm luger 1902, the .223 in 1957 (as an experimental)
the .45acp in 1905, the 30.06 (a modified version of the original 1903 cartridge) adopted in 1906 as the standard military cartridge, I don't really see any connection between them as far as deliberate design.

There are many cartridges that use the same shell plate in reloading presses. This is because the differences in rim and groove diameter are minimal and fall within tolerances enough to not warrant making a different plate.

One thing the common(close enough for government work) base of the pistol and rifle cartridges provides for is rebarreling a rifle in a pistol caliber without having to modify the bolt. There is a company that sells a .45acp kit for the 8mm Mauser. By changing the barrel and inserting a new mag well, it uses standard 1911 magazines. No work is necessary on the bolt at all.

 

[USMA-82]

The comparison shows you how, over time, costs and logistics concerns won out over common sense and experience. At the beginning of the 20th century, we knew that bigger, more powerful rounds stopped the enemy cold. At the end of the 20th century, we started being concerned about costs and how many rounds of ammo we could fit in a cargo ship bound for Vietnam.

So we scrapped the venerable 1911, and sent our M14's to "Captain Crunch" since we had made the leap to modern weapons.

Fast forward a few years later, and we find the vast distances in the desert and shooting hilltop-to-hilltop calls for a larger caliber rifle. Oops! We got rid of them, didn't we?

Now the Army has had second thoughts about the 9mm Beretta's and wants to move back to the .45 pistol. What a surprise!

Hopefully, we've finally learned that smaller is better for some things - computers, cell phones, etc - but bigger is better for others - like bullets.

 

[Coyote33]

OK, silly question. Are there any planned rifle/pistol cartridge combinations in the military?

We all know that there are pistol caliber carbines in both revolver and autoloading calibers, but what about military applications? I guess the Thompson, Uzi, etc. are closest, but those are technically carbines also and not rifles, right?

 

[Finalygotabeltfed]

OK, silly question. Are there any planned rifle/pistol cartridge combinations in the military?

We all know that there are pistol caliber carbines in both revolver and autoloading calibers, but what about military applications? I guess the Thompson, Uzi, etc. are closest, but those are technically carbines also and not rifles, right?

Correct, a carbine usually fires pistol caliber ammo.

I think that they are pretty much kept separate in both design and application. The M1 carbine was an expediant application to enable those who would be normally only carrying a pistol (1911 in .45acp) to have a bit more firepower although it was issued as a primary weapon to many units. When in Korea in the 70's, I saw that many of their army and marine units carried them as a primary weapon. They don't have the ability for long shots like a .308, 8mm, 30.06.
Rifle calibers and intermediate cartridges are reserved for rifles and medium/heavy machinegun use.

 

[Scrivener]

The .45 ACP and .30-'06 have the same dimensions at the base and use the same shell plate, if you reload.

I suspect that this is also true for 5.56 and 9 x 23, as the latter was, supposedly, derived from cut-down rifle cases. This gave an ID suitable for a 9 mm bullet, with rifle case thickness to take the pressure.

I probably should have checked that theory out BEFORE buying the shellplate for the Dillon, as I already had a .223 caliber conversion.

 

[vellnueve]

Carbines are classically defined as shorter versions of the standard infantryman's rifle. The M4 carbine, the M44, the M38, the No 5 Mk I are all carbines.

The Thompson and Uzi fall into the submachinegun category. An automatic shoulder arm (or in the case of the MP5K etc a variant of one) that fires a pistol caliber cartridge.

I would refer to pistol caliber semi auto rifles as light rifles.

The M1 carbine isn't strictly a carbine by the definition I suggested above, but it really is more of a light rifle (the .30 carbine is a rifle round, bottlenecked or not)