[Rich Z]

A while back there was a thread on this site somewhere about a comparison between these two rounds. Wish I could find it now......

Anyway, I was browsing through RCBS's list of reloading dies and noticed that they don't list a 7.62x51. Only the .308. Now I have a small base .308 resizer die that I have used forever for my reloading, and have fired these rounds in both military style guns as well as regular commercial hunting rifles. No problems to speak of. The rule of thumb I was told way back then was that if you plan to shoot the rounds in a semi-auto, then you need to reload using a small base sizer die.

Is there any substantial difference in the resized diameter of those cases that could be significant depending on the type of gun those rounds are fired in?

Just curious.....

 

[John in AR]

I'd be interested as well. I don't reload .308, but I do sometimes shoot milsurp 7.62x51 through my two .308 bolt guns. Never had a problem, but it would be interesting to see what any real differences are.

 

[Garand]

http://www.303british.com/ section .308 vs 7.62mm

Do you have a military surplus rifle chambered in 7.62 x 51mm? If so, I'll bet part of the reason you bought it was to get a "308 Winchester" at a really low price. Well, you screwed up. It's like looking at a Northern Pike and a Muskie. They're close yes, but each is distinctive, and you have to understand what you're looking at.



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Early in my military career, I worked on the FNC1 rifle (7.62 NATO). For someone that had previously handled and fired only shotguns and hunting rifles, this was a real treat! Maybe being an armourer wasn't going to be that bad! It was only natural then, that curiousity would generate questions and comparisons about what I thought was the same cartridge - 308 Winchester and the 7.62x51mm NATO.

FNC1

As part of my personal battery, I had a Midland 2100 chambered for 308 Winchester. This rifle was made in England by a small company - Midland Rifle Co I believe - but owned by Parker Hale. Having lots of military 7.62x51mm rounds available, I shot them from my 2100 from time to time. There was never a problem chambering or firing the military stuff. It was a pleasant diversion over the long (read boring) periods spent at the range for base small arms qualifications.
(I traded it off some years ago for a Smith & Wesson Model 686. It's the only rifle I ever regret losing! - Steve)

Around this period I discovered that shooting reloaded cases fired from an FN was virtually impossible. They didn't want to chamber. My frustration led me to ask an older armourer what was wrong. In a nutshell, he told me that they probably didn't fit because they stretched. I was using a Lee Loader in 308 Winchester and didn't know that they only resized the neck, leaving the rest of the case untouched. The shoulders were blown forward on initial firing, so the case was simply too long to fit my rifle's chamber! Hmmm...
I tried the gauges from work in my own rifle. What a shock! None of them would fit! The corporal brought a set in from home and explained the difference. Here's what I discovered.

308 Winchester (SAAMI) Gauges Shop (Military) Gauges
GO - 1.6300" GO - 1.6350"
NOGO - 1.6340" NOGO - 1.6405"
FIELD - 1.6380" FIELD - 1.6455"

The gauge sets were different too! What gives? He told me that the dimensions of the two new and unfired cartridges were basically the same. The difference lay in two areas - chamber size and cartridge makeup.

Chamber Size
Look at the picture below. The top chamber represents a military rifle, the bottom one a commercial sporter. With many military rifles, their chambers can be significantly longer than, say, a Remington 700. Note that the military chamber would fail a NO GO check, but pass a FIELD check using the proper shop (military) gauges.

There is a .013" difference in chamber length however, between these two "Safe & Serviceable" rifles!

 

[Rich Z]

Do you have a military surplus rifle chambered in 7.62 x 51mm? If so, I'll bet part of the reason you bought it was to get a "308 Winchester" at a really low price. Well, you screwed up. It's like looking at a Northern Pike and a Muskie. They're close yes, but each is distinctive, and you have to understand what you're looking at.

Hmm, "really low price" .308? Well let's see if I can remember what .308 military style rifles I have....

FN/FAL 50.00
FN/LAR 50.63
FN/FAL 50.42
H&K Model 91
IMI Galil Standard
IMI Galil ARM
M1A National Match (2)
SIG AMT (2)

I had an AR-10 in .308, but converted it to .243.

Actually the only bolt action .308 that I have is the Savage 112 FVSS Warrior. But I am toying with the idea of adding a FN SPR to that short list.

BTW, I had to cheat and look at my gun inventory sheet.....

No, I don't think "cheapness" was part of the equation in my buying decisions.

So, are genuine military issue rifles in 7.62x51 and the ones sold to the civilian market converted to .308?

Now you've got me wondering if that Hirtenberger ammo I bought says ".308" or "7.62x51" on the cases. I thought I bought it as "military surplus".

 

[Garand]

Rich , I brought that over from .303British.com, it was written in Canada. About 15-20 years ago we had a massive influx of Israeli Mauser K98K in 7.62mm & shitty old Indian FN L1A1's. At one time they were worth about $150.00 a piece.

 

[Rich Z]

Sounds like the original author tends to jump to conclusions.....

 

[Piemaster]

Here is a little 308 vs 7.62x51 http://www.fulton-armory.com/308.htm

 

[Aslan]

So, let me ask a dumb question....what happens if you use .308 win headspace gauges to set the headspace on a military rifle?

Or, is this just a non-event kind of thing where it doesn't matter?

:devil:

 

[DaRkWoLf]

Headspacing

The gauge wont be 100% accurate. If you continue the .308 win guage to check for wear you can get a reasonable idea of whats happening, even though the numbers are a little off.