Comparing the .308 with the 30-06...

**Son** · October 1st, 2009, 02:03 AM

So i have been told on numerous occasions that the .308, 30-06, and the 7.62 are the same. I belive they are the same size bullet, but whats the difference between the three?

**762xIan** · October 1st, 2009, 07:35 AM

No they aren't.....the bullet diameter is the same.....308, but the cartridges themselves are different.

This does create some confusion to new members to the shooting sports....learning all the technical details about ammo!

A .30-06 cartridge case is 63 mm in length, and .308 is a bit shorter at 51mm.

7.62 mm, is the metric equivalent of .30 caliber or .3 of an inch.

There are many .30 cal/7.62 mm cartridges around.

Short list of some.....30-06, 7.62x51 Nato, .308, 7.62x39, .30 Carbine, 7.62x54, the list goes on and on.

The bullets themselves are the same diameter, but come in different weights and types for different tasks.

Hope this isn't all that confusing and hope I helped!

**mikepro8** · October 1st, 2009, 08:17 AM

they are able to shoot the same size and weight of bullet, the biggest difference i performance i think is 150 fpe (foot pounds of engergy). The '06 can reach out a bit further than the .308.

**MaxPower** · October 1st, 2009, 08:33 AM

actually not. IIRC, x39 and x54R are .311 diameter bullets as they are measured by Groove and not Land dimensions. Off the top of my head, I don't remember if it's G to G, G to L, L to L or what. How's your 'google fu' feeling today?

**762xIan** · October 1st, 2009, 11:54 AM

Originally Posted by MaxPower

actually not. IIRC, x39 and x54R are .311 diameter bullets as they are measured by Groove and not Land dimensions. Off the top of my head, I don't remember if it's G to G, G to L, L to L or what. How's your 'google fu' feeling today?

Yes I should have worded my post a little better, you are correct, 39 and 54 use .311 bullets, as does the Brit. .303.

I was trying to point out more or less where the headache comes in for the new shooter and all the different variables and names that come with different ammo, even some calling themselves 7.62, which technically aren't.

It isn't enough the new shooter has to learn about guns, but learning about the ammunition itself will drive you crazy.

But hey, that is one of the reasons I come here, I don't mind answering questions. I had some patient folks "school" me at one time.

**Tomcat088** · October 1st, 2009, 01:19 PM

You've gotten some good and accurate information here. The .308 and the .30-06 are different cartridges, and the information that people have given about them is correct. I did want to cover something that you hinted at (maybe without knowing) that other people have not quite gone over.

Many people will say that the .308 and the 7.62 NATO (7.62x51mm) are the same cartridge and that you can use them interchangeably. This is actually NOT true. I made a post about this on another thread the other day, and I'll link it here as well as kind of water down the post here. http://forum.pafoa.org/rifles-42/734...tml#post911748

Basically the catridge has the same dimensions, but they do have different operating pressures. The .308 operates at higher pressures than the 7.62 NATO, and typically the NATO brass is thicker, meaning it has less case capacity. One of the major differences is what the chamber dimensions are though. On a 7.62 NATO, the headspace is different than on a .308, and the brass is allowed to stretch a little more. This is not a problem as there is more brass than a normal .308. IF one was to shoot .308 in a rifle that is chambered for 7.62 NATO though, it could POSSIBLY cause a problem. This has to do with different operating pressures, different headspace, and amount of brass in the cartridge. It is perfectly find to shoot 7.62 NATO in your rife that is chambered for .308, but not necessarily smart or safe to go the other way around. Sure there are people that have done it, and I'm sure there are some people that will say that they do it all the time and don't have any problems. Either way, it's very possible to have problems, and have a failure that could completely ruin a rifle and possibly injure or kill you.

I did want to get that out there, just to clarify to the issue, and just to help you understand on some level that while they are almost the same, the are NOT the same. You probably will not understand everything right now about headspacing, and some of the specifics but that's ok. You'll come to understand it in time, just remember that they're not the same and you should exercise some caution. Be safe, and great question.

**Son** · December 16th, 2009, 05:22 AM

Originally Posted by MaxPower

... Off the top of my head, I don't remember if it's G to G, G to L, L to L or what...

what does this mean?

**stephpd** · December 16th, 2009, 06:22 AM

Grove to grove, grove to land or land to land. The actual bullet diameter is .311. But after being run through the rifle barrel it is smaller by a few thousandths. Where you measure this was the question to come up with the .308 measurement.