Surplus 7.62 ammo ?

[woodland]

Ok. I bought some surplus ammo for my .308. I don't know what country it is from, but it is in a green "battle pack" with a lable that says "140 RD 7.62X51 BALL M1A2." They are in cardboard boxes of 20 rnds each. The headstamp does not have the NATO mark, it just has "12" and "84."

Now, my concern is, when I fire them it is hard to raise the bolt handle. Once the handle is raised, the bolt pulls back just fine and the shell extracts easily, but to raise the bolt it is quite stiff. Tried other ammo and all is normal. It is just this ammo. Another thing I noticed is the neck shows black smoke residue down to the shoulder.

So, should I dump the ammo? Is this a pressure problem? The rifle is a Rem. 700VS. I don't see any pressure signs on the primer or anything else.

Thanks!

 

[lt dan]

sounds as if you might have ammo from the old sadf(south-african defence force). is there a colour around the primer -green or purple?. i own a 308 and has shot many times with these rounds with no problems. the problem you are talking about is a concern. by the way the rounds with the green lable is a competition round, vary accurate.if it is sadf ammo it will explain the lack of the nato stamp. i always thought that the reason why the boxes contain 20 rounds is because the rifle the sadf used in 7,62 could take 20 rounds in a mag. in front of me i have such a cardboard box and the rounds have the numbers 12 and 84. if i remember right there were about 4 different numbers or sets of numbers. if it is sadf ammo it was made by a company called krygkor today it is known as denell. i hope you get an answer for the problem i will see if anyone over here had such a problem.

 

[woodland]

I think you hit it on the head. They are just as you describe, and the sealer is purple. I don't have any of the fired brass right now, but here are some pictures of the new stuff and packaging. (I felt like playing with the camera!)

 

[woodland]

Any ideas?

 

[lt dan]

that is sadf ammo. the sadf used it in a rifle -the R1-.this is a FN variant. this was replaced with the R4 5.56mm(Galil variant). when i was a tanker we used the smaller version the R5. allthough not as accurate as hunting ammo i have never heard of the problem you have. so i phoned a guy who used to work for one of the companies during the apartheid era when this ammo was made. here is his aswer the best i can put it in english(not my first language!)

the problem might be two fold or a combination of two problems -headspace and pressure.

hunting ammo does not create the same pressure as mill ammo due to the fact that the mill ammo has a lighter bullet. so that might be the reason(higher pressure). but it can be that the added pressure now unmasks an allready existing problem of headspace. something you did not know about because the normal ammo didnt create the same pressure. apparently this is not so uncommen with these ammo and according to him most hunters ignore it.

some of the things he said made no sense. when i asked about this he got very technical in his explanations. i then decided to simply repeat the answers to you.

in those days all guns and ammo manufacturing companies was state owned. collectively known as Krygkor. within krygkor there were two companies that is applicable to your question. the first was called Musgrave-they manufactured hunting rifles- the second IS called PMP. they manufactured(and still do) the ammo in your photos. so when some customers of Musgrave started complaining about the same problem you talk about with regards to the PMP ammo, research was done and above mentioned answer was found.

if you have more questions i can ask again.no problem

TIA mate!

 

[woodland]

Hey, that was great! Thanks for looking into that. I guess I'll find something else to do with that ammo. I don't think I want to chance putting any more of it through my rifle.

 

[44 AMP]

Pressure can indeed be the reason....

But not for the exact reasons given. Consider that both GI and commercial ammo have "industry standard" limits (50,000psi for US GI ammo, and 52,000 for commercial IIRC), and foreign made ammo sould be somewhat close to these specs.

But, the devil is in the details. I do not believe that the difficulties you are encountering are because of the "higher pressure" of the military ammo (in overall terms, it probably isn't higher pressure that what you normally shoot), what is happening is the difference in how your rifle handles the pressure.

Very sooty case necks are a sign of the case not completely sealing to the chamber. This is not a sign of high pressure, it is a sign of (nearly) the opposite. The pressure needed to properly seal the case against the chamber during firing is partially dependant on the hardness (ductility) of the brass casing. "Softer" cases will seal more completely at lower pressures, but at higher pressures (and heat) may tend to "stick" in the chamber, a serious concern when automatic rifles and belt fed weapons are being fed. Therefore, much military ammo, (especially made outside the USA) tends to have harder (or stiffer) brass cases than US commercial ammo.

What is happening is that you are shooting foreign milsurp ammo in your bolt gun, and having smokey necks and a hard bolt lift. What may be a cause of it is the cases not sealing to the chamber as well as the commercial ammo you are used to, allowing some powder gas to flow back around the neck "smoking them", and because of the reduced grip of the case in the chamber, it increases the rearward thrust of the case head against the bolt face. This increased thrust "seats" the locking lugs harder against their mating surfaces, and you feel it as a more difficult bolt handle lift.

I cannot, of course be certain without actual examination of the rifle/ammo, but it seems the most likely explanation to me, based on your description.

A few rounds like this should not damage your rifle, but if you make a regular practice of firing this ammo (case lots) , you ought to have your rifle checked periodically for battering and setback of the locking lugs, or their recesses. Not likely with a modern gun made of modern steels like your Remington, but well known to happen with older bolt guns, especially milsurp rifles converted into other calibers.

It is somewhat ironic that the hardness of the brass, which is intended to provide the best reliability in military auto rifles is causing you some difficulty in your bolt gun, but it is not an unknown situation.

And neither is the reverse, having some military autoloaders choke when fed commercial (or overly soft cased GI ammo). There is a field fix for this problem, which usually works (lightly oil the ammo) but it has its own drawbacks.

 

[rezmedic54]

Ammo

Best answer is that 7.62 x 51 ammo is just slightly larger then standard .308. This why you have a problem with it I had the same problem when attempting to reload some 7.62 cases bolt hard to close but would close. The case is just a bit longer then the .308 case. If you reload them you'll have to run them through 2 to 3 times once to size them close and then you'll need to trim them to length and then resize with possibly have to trim them again. At least this is what I needed to do also the flash hole is smaller then normal and my regular decapper wouldn't work as the pin was to large. Took some figuring out but now all is well with the world.

 

[woodland]

Thanks guys! I haven't shot much of it. Maybe 40-60 rounds. I think I'll play with it a little and do some measuring compared to my Black Hills stuff. Thanks again for all the info!

 

[gettyleigh2112]

the guy that was talking about head space and pressure nailed it, at least i think. I know this is an old post, but just to add to it, check out wikipedia for an article title "the delta L problem." It has to do with different mfg specs by different certifying authorities. I threw the link in below anyhow. You might want to get a set of "headspace gauges," some gunsmiths do have them, and check the chamber of your rifle. Sometimes the tolerances are too tight or too loose. This can happen after too many rounds are fired. Some rifles just need a new bolt, others can be adjusted . . . its best to contact a gunsmith to have it checked.

http://en.wikipedia.org/wiki/Delta_L_problem

 

[lt dan]

getty, if this problem only occurs with mil surplus ammo AND the rifle uses a
k98 i would still use the ammo.

 

[NWCP]

I run surplus ammo though my HK91. My CZ550 FS prefers .308. I have shot some NATO surplus through it, it was German if I remember correctly, and it worked. The Spanish Santa Barbara was good as well.