7.62 NATO/.308 compatability

The very first link repeats the myth that 7.62x51 is 50,000PSI It's 50,000 CUP not PSI Quit mixing up units please. Tried of seeing that misinformation repeated over and over again..
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Average operation pressure of 7.62 NATO M80 Ball is 48,000 CUP or 50,000 PSI EPVAT ( the international standard).
The operating pressure of M118 Special Ball and M118 LR are 52,000 CUP, no EPVAT equivalent given.
HPT (military Proof loads) are 64,000 CUP.

Theres no direct correlation between CUP and PSI readings and the difference varies from one cartridge type to another because of differing case capacities and configurations. A few cartridges such as the .30 carbine have CUP and PSI figures that are identical.

PS
Most Milspec propellents contain flash suppressant and coolant additives , usually Calcium based, that add an abrasive element to fouling and increase bore wear.
As for laquer sealents at the case mouth and asphaltum sealants inside the case neck, I've cleaned enough military rifles to know that these do leave deposits in a bore.
Laquer coated steel cases are a problem on their own, and the waxy protective coating found on some older brass MG cartridges may have a deletrious effect when used in a rifle. Only heard of wax coating used on some South African .303 MG ammo placed in long term storage.
 
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R. Demon, your comments on the asphaltum sealant in military ammo case necks and additives in powders used in them don't reflect what I've experienced. They've have had no impact on accuracy and barrel life in both myself as well as many others wearing out match grade barrels. We've got the same accuracy fall off with 7.62 military sealed ammo with additives in powder and commercial .308 unsealed ammo with no additives in powder for the life of the barrels. It is the same rouind count as one of the USA's best match bullet makers got with their match grade barrels testing 30 caliber match bullets for accuracy. Typically 3000 rounds before accuracy degraded by 30 to 40 percent. The same number test barrels used at the arsenal got testing 7.62 match and service grade ammo; all with asphaltum and powder additives you mention as told to my by one of their ballistic engineers. Therefore I can only conclude that all those addititives and sealants have no effect on neither barrel life nor accuracy.

I've not noticed any significant difference in how dirty barrels were whether or not additives or sealant was in the ammo or not. And I've worn out more than a few barrels with both ammo types.
 
Just like .223/5.56 and .308/7.62 if there was such a big danger that some keyboard commandos make it out to be manufacturers would have come up with one standard many many years ago. Could you just imagine all the lawsuits for blown up guns. Trial lawyers would have have a field day. Fact is its a non issue.
 
I'm sure matchgrade barrels get far better and more frequent cleanings than the milsurp rifle barrels I've cleaned up over the years.
I've cleaned up bores with grooves packed solid with fouling hardened by decades of storage without ever having been properly cleaned. When finally broken loose it comes out in palm fulls.

Any grit introduced into propelents can be a factor in wear.
The older ground glass added to sensitise primers for example, before barium salts were substituted.


Some milsurp ammo I've broken down for components had globs of sealant that intruded into the powder space, properly assembled ammo should have no more than a smidgeon near the case mouth.

I've made scrapers from brass tubing to clear out fouling from the chamber neck that was thick enough to cause excessive pressures when a cartridge was fired.
The hardened fouling looked like scrappings from an old phonograph record, coming out in thin coils. A dry crusty deposit under that looked more like graphite and came out in dusty granules.
Never saw anything like it on any commercial firearms no matter how abused.

With an SKS I cleaned up a couple of years back the fouling dissolved in the solvent into a laquerlike mess that took forever to get out.
The bore looked like a patch soaked in stock finish had been run through it till it was all gone. That had to have come from the asphaltum sealant and laquer case coating of Soviet ammo.

If every type of milspec ammo was as well put together as US government ammo there'd be little to worry about on these scores.
Some NATO interchangeable ball is atrocious.
 
Lots of good info from knowledgeable and experenced guys.My conclusion for myself and advise to others would still be, as a general rule, not to run anybodys FMJ in your fine bolt action hunting rifle. Stick to premium hunting ammo.:p
 
"My conclusion for myself and advise to others would still be, as a general rule, not to run anybodys FMJ in your fine bolt action hunting rifle. Stick to premium hunting ammo."

Your choice, but no need to at all.
 
Someone needs to send Lapua a letter telling them their fine FMJ match bullets will ruin fine match grade barrels. Mayby they'll stop selling them.

Most bullet making companies use the same jacket material for both FMJ sporting bullets and precision hollow point match bullets. How in the dickens will one effect any barrel differently than the other?

What about all those FMJ match grade pistol bullets shot winning matches and setting records? Who's gonna tell those folks the bullets they use are bad for their match grade barrels?

If anyone feels FMJ's are bad for any barrel, that's fine, you can't go to jail for what you're thinking. But such belief's fly in the face of reality. This is one of many myths in the shooting sports. But some folks cannot reason away from it; too bad for them, but such is life.
 
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Jehu,
Some of the finest bullets that are made have a full metal jacket (FMJ - which is actually a copper jacket, maybe you equate "metal with steel?). The fact that copper covers the tip of the bullet has absolutely zero effect on the rifling that it never touches. Thus it will not harm even the finest hunting rifle. As a matter of
fact, some of the finest hunting rifles fire a completely solid copper projectile.
The difference in FMJ bullet construction will have an impact on terminal ballistics compared to a PMJ (softpoint, ballistic tip, HP, etc.) - meaning it will most likely not expand as quickly or as much and probably have more penetration in game.
Differences in jacket thickness do vary but that cannot be determined by the designation of FMJ alone. Even the thickest or hardest will not substantially wear your bore more than one just a bit softer as Bart has tried to explain. I don't personally know Bart, but I have read a lot of what he writes .... He knows what he speaks of. Also, the construction of the bullet will make no difference to a fine rifle regardless of the action; whether bolt action, semi-auto, pump, break open or other.

There is already a lot of mis information here in this post, but we don't need to recommend the idea that a FMJ bullet is not suitable for for fine fire arms based off of what seems to be a poor interpretation of information.
 
MJN77, your question is patly related to this discussion. Springfield recommends using only milsurp 7.62x51, but that is only due to the design of the rifle and the usual components of military ammo. The M1A has an inertial firing-pin and the manufacturer doesn't want to get sued if the softer, more sensitive primer of a commercial round goes off when the round is chambered. Military ammo can have thicker primer cups to better withstand MG use. You find the same firing-pin design in AKs, ARs, SKSs, but only the SKS seems to share the same concern.
 
Oryx, I did not give any misinformation on this thread, in fact I have learned a thing or two about FMJ variations. As Rainbowdeamond pointed out older FMJ and some from other countries have coatings and additives that could be damaging to a firearm so for me I don't want to take the risk. You and Bart evidently know which FMJ is clean and what is not ,so shoot it in what ever firearm you want. I still see no need to shoot FMJ in my fine bolt action HUNTING rifle.
 
I didn't mean to imply that you were responsible for the misinformation, but rather speaking in general about that.

I have been reloading for almost 20 years and still learn every day
 
Only if you reload does it matter, military loadings -mm, sry dont have number keys right now- are in thicker cases therefore require less powder for optimal operating pressure. as for production ammo, between me and my roommate, we've put a few thousand of both CBC brazilian milsurp ammo as well as regular hornady and american eagle hunting ammo and it really doesn't make a difference except the occasional hot one you get in a brick of milsurp. fyi, i have a vepr, he has an older surp built m1a
 
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