Bullet Diameter

Are you asking for the bullet diameter on .30-30 Winchester? It's .308.

If you buy some .308 bullets for a 30-30 you will find some manufactures make their 30-30 bullets .307 diameter and some make them .308. (well almost)

In front of the crimping groove is a smaller diameter to help keep the chamber pressure down on the low intensity 30-30 cartridge with a "rated" chamber pressure of 40,000 cup. If I remember correctly the factory ammunition in loaded to 38,000 cup or lower due to all the older 30-30 rifles still being used.













I would load the Hornady 30-30 170 grain bullets in my 30-06 at 2,500-2,600 fps and it would really thump the deer in eastern wooded areas where most shots were under 40 yards. (30-30 magnum)

USA designed and designated 30 caliber or 7.62 is almost always .308 nominal.

Russian 7.62 is more like 3.12 or there abouts. I think Russian designs should be 7.7mm, but they called it 7.62 for some reason?

To be brutally correct 7.62mm = .300 exactly

If you purchase .307 (older) or .308 (newer) bullets for it they will fit fine just remember they have to be round or semi round nosed bullets to prevent "mag fire" or "chain fire" unless they are the new LEVERevolution--which would be the ones to get just for the better accuracy and "slightly" flatter trajectory..

Why not get a bullet mold for .30/30 Win or .30 WCF and cast your own then you'll be positive.

.303 British (7.7x57Rmm) 7.7x58mm Arisaka and 7.62x54Rmm Russian all take a .311/312 bullet

"...Russian 7.62 is more like .312..." 7.62 x 54R uses a .311" bullet. The 7.62 x 39 uses the same bullet diameter, but with a much lighter bullet. 7.62mm is the bore diameter on both.
"...difference between the 30-30W cartridge vs. the .308..." The .30-30 is a rimmed bottle necked cartridge with a nominal max velocity of around 2400 fps with a 150 grain bullet. Max bullet weight of roughly 170 grains. The .308 is a rimless bottle necked cartridge with a nominal max velocity of 2700 to 2800 fps with a 150. Max bullet weight of roughly 200 grains.

Easiest way to remember: American .30 calibers are .308, non-American (7.62xwhatever) are .311.

IIRC, '.30 Caliber' was designated from the lands, not the bullet diameter.

We (Americans) measure bores on the grrove, and the Germans always have as well I believe. Most of Eastern Europe & Asia (If I'm remembering correctly) measures bores on the land. The Brits measured on the land at least until WWII - their .303 British measures .311-.312 here in The States. I believe the Brits & the rest of Western Europe adopted the US method when NATO was formed. I'm not sure if SEATO caused a similar standardization of bore measurement. ( That's also all assuming an even number of lands & grooves - I have no idea how exactly you measure bore diameter on odd land / groove rifling like 5R).

IIRC, 9mm Makarov (9x18) is .362 diameter in US Measurement, while 9mm Luger / NATO (9x19) is .355 diameter.

Yeah, Makarov's an odd one. (.365, IIRC). Essentially, where 9mm Luger came about by de-necking .30 Luger, Makarov came about by de-necking and then removing the taper.

We (Americans) measure bores on the grrove,

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THIS American measures bore diameter in the bore and groove diameter in the grooves and is irritated by the Internet Culture blurring the difference.

And you cannot tell what an advertising agency is going to do.
The .308 Winchester and the .300 Winchester Magnum, although very different chambers, have THE SAME bore and groove diameters.
7.62 mm = .300" which is their nominal bore diameter.

The Lazzeroni 7.82 Warbird confuses matters by being one of the very few cartridges with a metric designation for groove/bullet diameter. It is still a nominal .30 caliber by the old dictionary definition of caliber = bore diameter and shoots the same size bullet as .300 WM or .308 Win. Or 7.62 NATO.

I have no idea how exactly you measure bore diameter on odd land / groove rifling like 5R).

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There are multi-point micrometers for such jobs, or the correct angle V block, a regular micrometer, and some math will give you an answer. There was a guy, since deceased, who had a selection of such measuring tools and would gauge any slug you sent him.

The article in Hatcher's Notebook about the rifling plans of 1903 Springfield and 1917 US Enfield is instructive. He shows how the five groove 1917 barrel with .310" groove diameter is actually "tighter" than the four groove 1903 .308 barrel; based on cross sectional area.

2075 RAMI said:

Alright, let me see if I have it.

Bullet Diameters:
.308 is .308"
30-30 is .308"
The main difference is the size of the casing along with the 30-30 casing being rimmed with the .308 weighing as much as 30 gr heavier.

Although I did not ask for 7.62 diameters, I thank you guys anyway as it is handy to know.

Bullet Diameters:
7.62 (x39)/(x54R) is .311"
The difference being mainly weight and the obvious longer casing of the 54R.

Thanks guys for your help.

--'Rami

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The .308 can weigh about 25 gr more then a .30 WCF as it doesn't handle bullets over 205 gr very well but the .308 calibres of the other 30s can go as high as 240 gr. because of larger case capacity/length.

You did ask for 7.62mm since that is what .30/30 Win is and .30/06 Springfield (7.62x63mm) and .308 Win (7.62x51mm) and .300 H&H magnum (7.62x72mm) and .300 Win Mag (7.62x67mm) and .300 WSM (7.62x53mm) and .300 RUM and .300 RSUM etc.

The difference between the x39 and the x54R isn't only case length (15mm) but the fact that the R in the 54 and everywhere else stands for Rimmed with the .311/.312 bullet also fitting the .303 British, .303 Savage and the 7mm Arisaka.

As pointed out, Euro dimension are different to American dimensions since one measure across the lands and the other across the grooves but they don't always market it that way e.g. 6mm Rem and .243 Win.

FYI .380 bullets (are actually .355"/9.0mm) will fit into a 9mm case and vice versa...9x19mm Parabellum or 9x19mm or 9mm Luger has a neck of .380 (9.65mm) and a bullet diameter of 9.03mm/.356".
.38 Spec fits into a .357 Rem mag revolver and fires just fine from it that's because the bullet it fires is .357 (9.1mm) but the cartridge mouth is .379 (9.6mm)
But if you use the true mathematical calculations 9mm = .35433"

Now, that you are completely and thoroughly confused best bet is to get a copy of Cartridges of the World and they break down everything for you--2009 Marked their 12th Edition and I think they are on their 13th Edition now--so there are lots of used copies out there but it's one book most shooters, gun collectors, reloaders keep, at least one maybe even two copies on hand...Most public libraries carry it as well.

I default to Mr. Watson.