7.62 x 39 vs. 7.82 x 51 (.308)

[44 AMP]

First off, lets be clear, cartridge names do have some relationship with their bore size, but only some relationship, and the actual bore diameter may or may not be in the name.

Some rounds are named for their actual bore size (land to land) some for groove to groove diameter, in both English and metric systems.

Some are named for the size they once were, and are not now, because of technical advances. Some are named by their inventors, some, the marketing department. Some are named for other reasons, such as .30-06 which is the caliber and the year of US govt adoption.

Now, as to the 7.62x39 and the 7.62x51, both follow the usual metric practice of bore size x case length in mm. Both are 7.62 because they have the same diameter bore (.3")

The .308 Winchester is the .308 Winchester because Winchester created the name as the civilian sales name of the 7.62x51.

In general terms, the NATO round was developed to duplicate GI .30-06 performance. The ".30 Russian short" (7.62x39mm) was made to meet a lower velocity and bullet weight standard. Essentially the 7.62x39 does not quite meet the performance of the .30-30. Close, but not quite the same.

Quite enough for many uses, but NOT the same as the .308 Win, by several hundred feet per second and without the ability to use heavier (150gr and up) bullets like the .308 can.

Other than the .30 caliber bore size the two rounds have little in common.

 

[Model12Win]

The .308 is an excellent stopper.

7.62x39? Not bad, but most of the older bullets designs were known to pencil through.

Even with the modern loads, .308 is still way more effective at stopping an agressor RIGHT NOW over the x39.

 

[Gunplummer]

I load 150 gr bullets in my 7.62x39 bolt gun. Probably will not equal the 30-30, but you can load them a lot hotter without a problem. It is one of the few hunting rounds I have loaded at the top end to get accuracy from it.

 

[emcon5]

Why would you want a putter when you can have a driver?

You ever putt with a driver?

I just don't understand.

Then don't buy one.

Faster is better right, so if a .308 is better than a 7.62X39, then a .300 Win mag is better still.

But wait, That is still not good enough, because a .300 RUM is even faster, so must be more better.

Hmm, if more is better, then we should make the bullet bigger too, right? So you should go to .338 Lapua, that would be more more better, but not quite better enough, so have to go to the .408 CheyTac. Nope, still better out there, the .50 BMG. That has to be as better as you can get, right?

Nope, there are still bigger faster rounds out there, have to go with a 20mm Vulcan, they make rifles for that, unless you want to go old school and find a Solothurn S-18 or Lahti L-39. Who cares if the rifle is over 100lbs, it is better, right? It has to be the mostest better there is.

Right?

 

[turtlehead]

That was the point I was trying to make, emcon5. Where's that d@rn sarcasm smiley?

 

[pappa]

Yeh, never try to consider "labeled" to be technically accurate. I have often wondered if some of this came from the transition from linen patched black powder bullets. As if a .311 ball wrapped in a patch did fit a .32 bore. Without SAAMI, etc during transition to smokeless, lots of room for various ways of expressing dimensions. Just a thought.....
As far as always buying the biggest and fastest, Cowboy, why buy an 8 passenger 450HP SUV when a 5 passenger 265HP Crew cab PU is all you need.
I love my .22RFs and shoot them the most. Pleasant to shoot, test of my skills for accuracy.
I'm glad for your interest and your question. Happy shooting.

 

[44 AMP]

Turtlehead, its this one...

I have often wondered if some of this came from the transition from linen patched black powder bullets.

when you are looking at why some rounds have names that don't match the actual size of the bullet used, you need to look at their history.

The reason many of our handgun rounds don't match name and actual bore size is due to the development history of cartridge ammunition.

The reason our modern .38's are actually .36s (.358") for instance, is because the early cartridges were actually .38s. They used a heel type lead bullet (like the .22LR still does today). The full diameter of the bullet (bore size) was the same as the diameter of the case. Later, bullet design changed, the inside lubricated bullet (the lube & the widest part of the bullet were inside the case) was superior to the heel type bullet.

But, this meant the bullet was a little smaller than bore diameter. Not a big issue with soft(er) lead bullets that upset and fill the bore well. Later, when harder bullets and jacketed bullets became the general standard, new gun bore sizes were reduced, slightly, for the best bullet to bore fit.


Of course there a lot more to it than just that, but that's roughly why our 38s shoot "36s" and our .44s are "43" (.429).

The .45 Colt didn't go through this, having come along after the era of heeled bullets. However, even the .45 Colt has been changed a bit. Pre WWII, the usual bore size was .454. Post WWII, through today, its usually .451/.452".

Rifle rounds went through their own changes, for many other different reasons. There's books about this stuff, I like reading them. You might, too.