Concerned and confused on .308 v NATO catastrophic failures?

[DefiantDad]

Was reading this:

http://www.303british.com/id36.html

Now I am confused and worried about my upcoming rifle choices (semi-auto and bolt).

I am not sure if the guy on that page is just trying to sell a book (no problem with that so long as the info is accurate) or what.

If .308 commercial has weaker brass than military, then what is going on with us firing store-bought .308 in battle rifles? (FAL, HK, M1A, AR in 7.62x51)

I realize many people buy milsurp to shoot, but I might not be doing that much especially if I am going to use the same .308 between my bolt gun (target/hunting) and the MBR. But I also don't want to have to worry that my guns will not fire milsurp.

What is the story here?

At least with .223 and 5.56 I know that a gun able to fire 5.56 can fire .223.

The above page makes it confusing.

 

[Vern Humphrey]

Yes, military chambers are looser than civilian sporting rifle chambers. And you can have a problem resizing once-fired 7.62mm brass to fit a civilian chamber -- especially machine gun brass, which typically is stressed more in firing.

But other than that, 7.62X51mm NATO will function fine in a civilian .308 rifle and vice-versa.

 

[Slamfire]

I am not sure if the guy on that page is just trying to sell a book (no problem with that so long as the info is accurate) or what.

If .308 commercial has weaker brass than military, then what is going on with us firing store-bought .308 in battle rifles? (FAL, HK, M1A, AR in 7.62x51)

I think the guy is trying to sell a book on loading 308 for military rifles. And other books.

I have weighed thousands of 308/30-06 cases and weight distributions can be all over the place. WWII 30-06 brass will vary as much as 20 grains between Arsenals. LC 308 is more uniform, usually heavier than commercial, but not necessarily.

This statement of his :

There is a potential problem with brass integrity. Commercial cases are NOT as thick as their military cousins. There is less brass, so if you use them in an original, unmeasured military chamber, there may not be sufficient material to stretch and fill the chamber without rupturing. That's bad!!

This is a untested supposition and shows the guy’s ignorance on the design of cases. This is a very complex issue, you have to consider tolerances between case and chamber, just how much the case is expected to expand and contract, the hardness of brass, by location, ductility, and these are just off the top of my head. If you are going to shoot a 308 in a 300 Win Mag chamber than the case is likely to rupture, but shooting a 308 in a NATO chamber, unless the brass case has a defect, why should it fail? Or maybe a better way to say it, why is it necessary for it to fail?

Thicker case heads are good, they resist expansion, less likely to pop a primer, less likely to be torn off during extraction, a little better able to carry pressure, but it is still brass. I do believe that thicker brass is better for auto matic mechanisms, if you don't hot load, thicker brass takes longer to expand the primer pockets and thicker sidewalls hold up better.

The worst brass I have used is Federal. Soft case heads that expand after a few reloads.

Ammunition makers have a difficult task, one that requires their ammunition to function in a wide variety of mechanisms. I would not worry about thin brass as much as I would worry about quality control.

As for anyone being an expert on 308 brass because they shot a FAL in the service, I would not consider that person an expert. FALs incidentally are very hard on brass because they are rear lockers and stretch the heck out of brass.

 

[Vern Humphrey]

To take two examples:

1. I have a Canadian M1905 Ross rifle. These rifles (which are in .303 British) failed in the trenches in WWI because of their weak extraction power. The Canadians, before switching over to the British Lee-Enfield, bored the chambers deeper -- on the theory that crud would be pushed into the chamber ahead of the case, and make extraction easier.

When I eject a fired case from this rifle, it looks like a .303 Epps -- shoulder blown well forward. I had to have Lee make up a special Collet Die so I could neck size and reload the cases.

2. I have a custom '03 Springfield in .35 Brown-Whelen (the most radical form of the Whelen.) To get brass for reloading, I load .30-06 cases with about 10 grains of Bullseye and a quarter sheet of toilet paper. The fired case has the shoulder blown well forward and the neck expanded to about .393".

I then neck resize, and get about 10 or more loadings from a case.

But other than that, I can shoot and reload it with no problems.

 

[DefiantDad]

Thanks for the details but... What's the recommendation in a nutshell? Ignore what that guy said, and just use good brand ammo for either bolt or semi? (although I thought Federal was a good brand generally for quality ammo?)

 

[Vern Humphrey]

Thanks for the details but... What's the recommendation in a nutshell? Ignore what that guy said, and just use good brand ammo for either bolt or semi? (although I thought Federal was a good brand generally for quality ammo?)

Yep. And I'd segregate the brass -- keep brass fired in a semi in one container, and that fired in the bolt gun in another. For one thing, that would ensure that you could neck resize and know the brass would fit.

 

[DefiantDad]

OK, interesting. Thanks.

 

[stubbicatt]

I shoot and reload milsurp brass for military type rifles.

For my bolt rifles I shoot commercial brass. It is easier that way.

 

[WardenWolf]

Some civilian .308 ammo is loaded slightly hotter than the military stuff. It normally doesn't matter, but a good rule of thumb is that a civilian rifle can always shoot 7.62x51, but a handful of military rifles may not be able to handle hot .308. A prime example are Enfields converted to .308. They can handle the NATO 7.62x51 loading, but you shouldn't try hotter .308 loads in them; the military loading is already pushing their action's limits. You just have to know what you're dealing with.

 

[jonnyc]

"a handful of military rifles may not be able to handle hot .308. A prime example are Enfields converted to .308. They can handle the NATO 7.62x51 loading, but you shouldn't try hotter .308 loads in them; the military loading is already pushing their action's limits"

Crap!!!
The only 7.62/.308 military rifles to be concerned about are the small-ring Mauser conversions. Factory ammo of either labeling is fine for any other military rifle.

 

[Vern Humphrey]

"a handful of military rifles may not be able to handle hot .308. A prime example are Enfields converted to .308. They can handle the NATO 7.62x51 loading, but you shouldn't try hotter .308 loads in them; the military loading is already pushing their action's limits"

Crap!!!
The only 7.62/.308 military rifles to be concerned about are the small-ring Mauser conversions. Factory ammo of either labeling is fine for any other military rifle.

And the small-ring Mausers are really not .308s. They are chambered for the 7.62 CETME, which is dimensionally identical to the .308 but loaded to much lower pressure.

 

[WardenWolf]

It depends. Some Enfields were converted. Others were new-production .308's (the jungle carbines) and reinforced. The converted ones are of questionable strength and really should not be hot-loaded.

 

[Vern Humphrey]

Actually, the Jungle Carbines were never used in .308 -- they were dropped before that round was available.

 

[Slamfire]

The Lee Enfield is a 1888's vintage bolt action, it was never very strong. Apparently it was not made from alloy materials, and the last version, the No 4, could be converted to 308 but the strength is so marginal, that all sorts of warnings from the British NRA have been published.

The warning not to fire No 4 Enfields in the rain apparently applies to all marks of Lee Enfields!

http://www.milsurps.com/showthread.php?t=20339

This is the current stance of the British NRA safety warning which first appeared in the Summer 2009 NRA Journal:
Safety Notice
Enfield No 4 Rifle Conversions to 7.62mm

A safety warning concerning the use of Enfield No 4 Rifle actions converted to 7.62mm was published in the Summer Journal.

After further consideration of all factors influencing safety of these conversions and consultation with the Birmingham Proof Master, the following advice must be adhered to in respect of the use of Enfield No 4 conversions:

• Owners of Enfield No 4 actioned rifles converted to 7.62mm currently proofed to 19 tons per square inch are strongly advised to have them re-proofed to the current CIP standard (requiring a minimum mean proof pressure of 5190 bar) which allows the use of CIP approved ammunition with a Maximum Average Working Pressure (MAWP) of 4150 Bar.

• Conversions retaining their original Enfield barrel or a replacement barrel as manufactured by RSAF Enfield are safe to use with commercial CIP approved ammunition, which complies with a MAWP of 4150 bar, loaded with any weight of bullet, providing they carry a valid proof mark, and are still in the same condition as when submitted for proof.

• Conversions fitted with any other make of barrel (such as Ferlach, Maddco, Krieger etc) should be checked by a competent gunsmith to determine the throat diameter of the chamber/barrel fitted before use.

• Conversions where the throat diameter is less than the CIP specification of 0.311” but not smaller than 0.3085” must not be used with ammunition which exceeds 3650 Bar MAWP when fired in a SAAMI/CIP pressure barrel.

• Conversions which have been checked and found to comply with Rule 150 may safely be used with any ammunition supplied by the NRA including the 155 grain Radway Green Cartridge, 155 grain RUAG Cartridge or any other commercial CIP Approved cartridges loaded with bullets of any weight provided that the ammunition pressure does not exceed 3650 Bar when measured in a CIP standard barrel.

• Owners of Enfield No 4 actioned rifles converted to 7.62mm who are uncertain as to the proof status of the rifle should have it checked by a competent gunsmith.

• Owners of Enfield No 4 actioned rifles in any calibre are strongly advised not to use them in wet weather or without removing all traces of oil from action and chamber prior to shooting.

• Enfield No 4 rifles which are fitted with a barrel which has a throat diameter less than 0.3085” must not be used on Bisley Ranges.

• Ammunition loaded with bullets of any weight which are of greater diameter than the throat diameter of the barrel must not under any circumstances be used on Bisley Ranges in any rifle or barrel of any manufacture.

 

[AethelstanAegen]

Owners of Enfield No 4 actioned rifles in any calibre are strongly advised not to use them in wet weather or without removing all traces of oil from action and chamber prior to shooting.

But weren't thousands of these things used in WW2? If that's true then Germans must have had an awfully "unsporting" advantage over the Tommies in a rain storm. Something just doesn't add up here. Certainly the even weaker Mk 3s were used extensively in all weather conditions during WW1. I could see the converted .308s having some trouble potentially but in .303 it just doesn't make any sense at all.

 

[Carl N. Brown]

Another gunshop/army buddy rumor I have heard is that the Spanish preferred to use a lower power and lower recoiling 7.62 CETME load as their service round, but they made their 7.62x51mm caliber rifles to use standard issue 7.62x51mm NATO service rounds as well, in case they had to use ammo from allied NATO forces. (They had intended to develop their own intermediate round like the German 7.92 Kurtz, Russian 7.62x39mm, but settled on an intermediate load for the 7.62x51 when forced to NATO standard.)

 

[madcratebuilder]

The Lee Enfield is a 1888's vintage bolt action, it was never very strong. Apparently it was not made from alloy materials, and the last version, the No 4, could be converted to 308 but the strength is so marginal, that all sorts of warnings from the British NRA have been published.

Those warning had more political motivation than safety motivation. The 7.62 Ishy Enfields (No1 action) and the 1970's 7.62 Enforcer Enfields (No4 action) are perfectly safe to use either 7.62 or .308.

The difference in the two is max head space spec. It is possible for a max 7.62 chamber used with the thinner .308 brass to experience a head separation, particularly if this brass has been reloaded. No one here shoots unknown reloads...right?

 

[Danco411]

If you just shooting and not reloading just be cognizant of pressure signs when using any new to you ammo. You really don't know what the load is for any old mil surp ammo. Fire a round ANC check the case head for and primer for flattening which is you first indication of over pressure. If the round is tight on ejection or won't eject until it cools then it is too hot a load and don't shoot it.

For hand loading I have gotten away from using mixed brass due to the lack of conformity. If I can score a big batch of a good headstand then ill use it in batch but never batch random cases. I have pretty much gone to using all LaKE City brass. There is good conformity even between year batches. Th LC brass is thick and tough and can be reloaded many times with proper prep and occasional annealing. Once you swage or ream the primer crimp its good to go. The pockets stay tight after many firings where Federal is looser than a Vega Strip walker after just once fired. That stuff is junk and only good for scrap.