7.62, 7.63, 7.65 mm???

[Don M]

Dumb question #452: Is there any difference among the subject calibers? I see guns advertised as having each of these.

[Ron Smith]

Don,
7.62 is .308 caliber as in the NATO rifle cartridge. 7.63 is approx. .310 caliber, and 7.65 is approx. .312 or as Tac said, usually used in designating .32 ACP or .30 Luger which is actually closer to .310- .312 caliber.

It's a bit confusing. Ron

[Don M]

For example, I recently was looking at one of the auction sites and there was a series of C96 Mausers, some listed as 7.62 and some 7.63. I was wondering if there really was a difference in the cartridges for these pistols.

[Dwight Gruber]

Don,

Pick up a copy of "Handguns of the World" by Ed Ezell 1981 Stackpole Books/1993 Barnes&Noble Books (may still be in print). It is an extremely good digest on the subject, and has an exensive section on military handgun ammunition which includes mm designations, common names, and technical details.

Worth the $$ and an interesting read, particularly if you can find one used.

--Dwight

[Don M]

Thanks to all of you for clarifying this. Now I can start formulating dumb question #453. So many options to choose from!!!

[Roadkill]

The way I view it is that the first number is the bore, the second the case length.


rk

[Edward Tinker]

Originally posted by tacfoley
Dear Mr Don - better still, get a copy of 'Cartridges of the World', 10th edition, by Barnes.

tac

Yes, this one is a good one Tac, has obsolete and currect rounds, helped me on many occassions when i did not know what the heck I was looking at.

Ed

[Steve Richards]

Just to show how arbitrary the numbers are, using 25.4mm = 1in the numbers work out :

7.62mm = 0.3000in
7.63mm = 0.3004in
7.65mm = 0.3018in
9mm = 0.3543in

Personally, I think that the manufactures just picked a number that was close to the bullet diameter and called it good?

Steve Richards

Tac,

Sad to say that the English Pit Rifle Range is closed until further notice. I guess the area is just too developed now to have a rifle range there. Safety concerns were given as the reason. To tell the truth, I am surprised that it lasted as long as it did.

[pipeman45]

I seem to remember that manufactures also used two different methods of mesuring the bore. Some used the lands and some used the groves. It's all a plot just to confuse me!

[Vlim]

Although we use the metric system over here in the Netherlands, we tend to use the most common designation for a certain round. The opportunist approach

We call the .22 long rifle just that, not a 6mm. 9mm is just 9mm and the Nato .308 is just called .308. .30 luger is an exception, as the round is more commonly known as 7.65 parabellum. .45 is called just that, we tend to drop the ACP.

Things tend to get confusing for our new shooters as I once saw a guy at the range trying to stuff 9mm rounds in his S&W 686 which was chambered for .38 & .357 rounds. We also spend a lot of time telling people that a flobert round and a .22 long rifle round are not exactly the same thing.

Don't forget that naming conventions were also used to stop people shoving the wrong rounds in the wrong guns, confusing the whole lot even more.

[Rod WMG]

Things are aggravated even more when people don't recognize the proper name for a round.

For example, if I go to a shop and ask for ".45 Colt" ammo, I'm invariably asked, ".45 Long Colt?" Or I'm simply handed a box of .45 ACP ammo. Now, some people dispute this, but I'm of the opinion that there was never such a designation, the confusion coming about because of the shorter .45 Schofield round which could be and was/is fired in .45 Colt sixguns. Then lately the issue is made more murky by Colt's threatening to sue those manufacturers who use the designation ".45 Colt" despite the fact that it's been in the public arena for a hundred years plus. They insist on folks using ".45 LC," not "Long Colt," but "LC." They can sue me, I guess, because it'll always be .45 Colt to me.

Oh, the ins and outs of loving guns and ammo!

[Don M]

Hmmm. Maybe my original question wasn't so dumb, after all.

[unspellable]

The caliber is the same as the bore which is the diameter across the lands or the diameter before cutting the rifling. The diameter across the groove bottoms is the groove diameter. Neither of which have anything to do with the cartridge's designation.

Any attempts to link actual measurements to cartridge names will lead only to madness. Consider the 44 Russian/Special/Magnum and the 445 SuperMag as an illustration of the lack of any rhyme or reason. All but the first have a 0.429 groove diameter, and are around 42 caliber or bore. Now consider the 44 S&W which has a larger groove diameter. Then there is the 44 Colt which has still another diameter.



As for the 45 Colt question. First came the 45 Colt.

Next came the 45 S&W, nicknamed the 45 Schofield. This created a problem for the army in that the 45 S&W had a wider rim which allowed only three to be loaded in the Colt SAA.

To get around this the government developed the 45 Government, nicknamed the 45 Short Colt wich had the 45 S&W case length and the 45 Colt rim. This cartridge was sold on the civilian market labeled as the 45 Short Colt.

Next came the 1909 Colt 45 chambered in the Colt New Service Model 1909. This cartridge had the 45 S&W rim width and a case about 0.010 inch longer than the 45 Colt.

Finally came the 45 ACP which was originally intended to duplicate the ballistics of the 45 Government or 45 Short Colt. The 45 ACP case is shorter than the 45 Short Colt case.

There was never a cartridge properly called the 45 Long Colt although during the time when the 45 Short Colt was on the dealer's shelves I am sure people called the 45 Colt the 45 Long Colt to distinguish it from the 45 Short Colt.

Now days we encounter store help who wouldn't know whozzit from whazzit no matter what the history was.

[tedpark]

And don't forget the 307 Win - as contrasted with the 308 Win - neither if which is either!

[Roadkill]

Don't forget the commercial aspects of it. The maker/inventor's name has little to do with the type/nomenclature of gun with which you can fire the ammo. IE .223 Remington ammunition fired in a Colt AR15 lower with a Bushmaster upper and an atttached Colt 5.56 NATO stamped barrel. As far as I know (which granted, is quite limited), Colt never has produced Remington .223 ammo, Remington has never made an AR15, 223. works fine in a NATO 5.56mm barrel which is not the specs for NATO 5.56. And Bushmaster has never made a round of Ammo.

[The Wizard]

Uspellable,

Although it is true that the .45 S&W did have a rim diameter larger than the .45 Colt, this did not prevent loading six round in the Colt SAA. In fact the US Army standardized the .45 S&W as the revolver cartridge during the Indian War period until the .38 colt was adopted in 1892(?). The M1909 .45 cartridge did have a rim diameter that prevented loading all six cylinders of the SAA.
The Wizard

[unspellable]

As I recall, the 308 Winchester has a 308 groove diameter, more or less standard for 30 caliber barrels in the US. The 307 is the rimmed version of the 308 and was called the 307 to distinguish it from the 308. Which gets us right back to the name may or may not correspond to either the caliber or groove diameter.

[unspellable]

The 45 Smith & Wesson or 45 Schofield did have a wider rim that could prevent chambering six rounds in the SAA. That's the sole and entire reason for the existence of the 45 Government or 45 Short Colt. The 45 Schofield was issued along side the 45 Colt as a secondary cartridge. The 45 Government was developed to work in both revolvers (At the slight risk of getting hung up under the extractor in the Schofield.) and became the single first line issue cartridge. It was the standard issue cartridge during the latter part of the Indian wars, not the 45 Schofield which never achieved any status beyond that of a secondary issue cartridge.

Note that if you buy modern brass headstamped 45 Schofield it usually has a 45 Government rim, a manufacturing short cut since it is just a cut back 45 Colt case. Thus modern 45 Schoefield headstamped brass will chamber six in a SAA. It's really 45 Government/45 Short Colt brass mismarked 45 Schofield.

The issue came up again with the 1909 Colt 45. It has the wider rim for a star extractor. The 1909 new Service was meant to take the 45 Colt as a secondary cartridge as the old army issue SSA's had been pulled out of mothballs at the time.