dangerous misinformation
I guess that to a certain extent I just don't understand what is going on here. For some reason there is apparently reluctance on the part of some folks to admit that .308 Win and 7.62 NATO are different cartridges. Others admit the distinction, but refuse to accept the fact that in some instances, the differences can be significant.
Why this reluctance exists, I just don't know. Sometimes I think I am failing to describe the significance of the differences adequately. Sometimes I think that egos just get in the way, that is, some folks just don't want to admit the realities of the situation because it requires altering long held beliefs on the subject. Some folks who are very knowledgeable about firearms have labored under the mistaken notion that these cartridges are identical for a long time. Having now been forced to acknowledge that they are not identical, they take refuge and solace in the position that the differences are insignificant. Perhaps for them admitting that there is a difference that can be significant is admitting that they are not quite as expert as they thought, especially for those who have made public pronouncements to the contrary. I am not an expert, but I have spent some time studying this subject. I didn't know there was a difference myself for years. I didn't own a rifle chambered in either cartridge, or have other reason to be aware of the differences.
At this point, on these boards, no one appears to be seriously challenging the fact that the specs for these cartridges are different, are set by different authorities, and that they are, in fact, different cartridges. Among other differences, SAMMI specs for .308 Win include a thinner case wall, and substantially higher pressure, than NATO specs for the 7.62 NATO. The issue now appears to be whether the differences are significant.
I take no issue with the statements made to the effect that folks have been shooting these cartridges interchangeably in modern battle rifles and modern bolt action rifles without apparent problems. For a number of reasons, I would not do so, but that is not the point.
My concern is with the persistent refusal of some folks to acknowledge the potential significance of the differences. My concern is with the use of the cartridges' designations interchangeably, or worse yet, perverting the designations by combining them into ".308 NATO". My concern is the practice of shooting these cartridges in older bolt-action rifles, originally designed and chambered to shoot much lower pressure cartridges, which have been re-chambered to 7.62 NATO. (I include the recent production Ishapore Enfields, which although originally chambered for the 7.62 NATO, are an obsolete design inadequate to safely manage the pressure these cartridges can produce. Supposedly these rifles are manufactured with better steel than the original Enfields, but there is good reason to question the quality control in their manufacture, and whether the supposedly better steel overcomes the problems posed by the obsolete design.)
A nightmare scenario: Young Joe Newby, low on bucks but anxious to join the fraternity of high-power rifle shooters, is looking for the least expensive way to join. Mislead by "common knowledge" and the unscrupulous practices of some dealers, he buys a surplus rifle, originally chambered for a cartridge like the 7x57 Mauser, which has been re-chambered to 7.62 NATO. He buys a quantity of outdated mil-surp 7.62 NATO. He is quite oblivious to the fact that this ammo was exposed to higher than desirable temperatures in storage; much of it now develops higher than normal pressure when fired. In several trips to the range, he shoots up three or four hundred rounds of this ammo. As far as he can tell, everything is fine, but unnoticed is the fact that the bolt is gradually becoming more difficult to operate after each shot. Unknown to him, the bolt is gradually setting back.
He goes to a gun show to buy more ammo. Grossly misinformed by an ignoramus behind a table, he also makes a luxury purchase, a couple of boxes of hot commercial .308 Win. Now he will shoot premium ammo, the good stuff, just like the people he admires and wants to emulate.
Back at the range, he shoots some 7.62 NATO as a warm-up, and then turns to the .308 Win. The first shot produces noticeably greater recoil, flash and report. The experience is exciting, much like the first time he drove a friend's hot rod. He doesn't realize that this ammo is producing significantly higher pressure than even the defective mil-surp; after all, he "knows" it is the same as the 7.62 NATO he has already been shooting, just higher quality. He barely notices the fact that the bolt is now significantly stiffer in action. He shoots several more rounds. By round 15, even he notices the bolt's increasing stiffness of operation. But unaware of the significance, he continues to shoot. He doesn't notice the severely flattened primers, and wouldn't know what it meant if he did.
Round 17 produces a hissing noise, and a tiny plume of smoke around the bolt. The bolt is very difficult to operate, and he must exert himself to open the action and eject the cartridge. Although he doesn't notice the primer damage, even Joe is now concerned that something is wrong. In fact, the primer has blown out, and gas has escaped around the bolt head and around the firing pin into the bolt assembly itself. He decides to shoot just one more round, only to see if #17 was a fluke.
It is one round too many. The rifle has developed more headspace than the case can manage. The primer blows out again, white-hot gas at 55,000 psi escapes into the bolt assembly. Almost instantaneously, stretched beyond its limits, the case fails around the head. The white-hot gas also escapes around the bolt head and into the action. The meager provisions of the design for escaped gas management are overwhelmed. The bolt is fractured, and the firing pin and bolt sleeve are blown back into Joe's face. Simultaneously the gas enters the magazine well and blows the magazine and stock to smithereens, showering Joe with splinters and shrapnel and causing serious burns.
Outrageous, you say? Can't happen, you say? Well, it can happen and it has happened, perhaps not exactly as I describe above, but close enough not to matter. A regular contributor to the boards recently posted about the damage and injury that resulted from what was almost certainly a case failure. While that damage was caused by attempting to fire a cartridge that was grossly mismatched to the chamber, the damage was caused by exactly the same mechanism as one described above, that is, case failure. And it happened in a modern rifle, well known for the strength of its design, with modern escaped gas management technology.
For every regular contributor to these boards there is an unknown number of visitors who read but do not post. Many, I suspect, are not nearly as knowledgeable about the art and science of shooting and firearms as are many of us. We do them a disservice when we perpetuate potentially dangerous mythology.
By simply acknowledging the facts, and using the correct terminology ourselves, we may very well prevent harm. I love the shooting sports and I don't want to see anyone hurt engaging in them. I certainly don't want to provide fodder to the "antis" who continually try to portray our sport as unreasonably dangerous. I don't mean to offend anyone, but when people make reference to ".308 NATO", or make statements to the effect that the differences between .308 Win and 7.62 NATO are insignificant, they are promoting potentially dangerous misinformation.
redcedars
"The true art of war lies in so sapping your opponent's will to fight that he surrenders without battle." Sun Tzu
Why this reluctance exists, I just don't know. Sometimes I think I am failing to describe the significance of the differences adequately. Sometimes I think that egos just get in the way, that is, some folks just don't want to admit the realities of the situation because it requires altering long held beliefs on the subject. Some folks who are very knowledgeable about firearms have labored under the mistaken notion that these cartridges are identical for a long time. Having now been forced to acknowledge that they are not identical, they take refuge and solace in the position that the differences are insignificant. Perhaps for them admitting that there is a difference that can be significant is admitting that they are not quite as expert as they thought, especially for those who have made public pronouncements to the contrary. I am not an expert, but I have spent some time studying this subject. I didn't know there was a difference myself for years. I didn't own a rifle chambered in either cartridge, or have other reason to be aware of the differences.
At this point, on these boards, no one appears to be seriously challenging the fact that the specs for these cartridges are different, are set by different authorities, and that they are, in fact, different cartridges. Among other differences, SAMMI specs for .308 Win include a thinner case wall, and substantially higher pressure, than NATO specs for the 7.62 NATO. The issue now appears to be whether the differences are significant.
I take no issue with the statements made to the effect that folks have been shooting these cartridges interchangeably in modern battle rifles and modern bolt action rifles without apparent problems. For a number of reasons, I would not do so, but that is not the point.
My concern is with the persistent refusal of some folks to acknowledge the potential significance of the differences. My concern is with the use of the cartridges' designations interchangeably, or worse yet, perverting the designations by combining them into ".308 NATO". My concern is the practice of shooting these cartridges in older bolt-action rifles, originally designed and chambered to shoot much lower pressure cartridges, which have been re-chambered to 7.62 NATO. (I include the recent production Ishapore Enfields, which although originally chambered for the 7.62 NATO, are an obsolete design inadequate to safely manage the pressure these cartridges can produce. Supposedly these rifles are manufactured with better steel than the original Enfields, but there is good reason to question the quality control in their manufacture, and whether the supposedly better steel overcomes the problems posed by the obsolete design.)
A nightmare scenario: Young Joe Newby, low on bucks but anxious to join the fraternity of high-power rifle shooters, is looking for the least expensive way to join. Mislead by "common knowledge" and the unscrupulous practices of some dealers, he buys a surplus rifle, originally chambered for a cartridge like the 7x57 Mauser, which has been re-chambered to 7.62 NATO. He buys a quantity of outdated mil-surp 7.62 NATO. He is quite oblivious to the fact that this ammo was exposed to higher than desirable temperatures in storage; much of it now develops higher than normal pressure when fired. In several trips to the range, he shoots up three or four hundred rounds of this ammo. As far as he can tell, everything is fine, but unnoticed is the fact that the bolt is gradually becoming more difficult to operate after each shot. Unknown to him, the bolt is gradually setting back.
He goes to a gun show to buy more ammo. Grossly misinformed by an ignoramus behind a table, he also makes a luxury purchase, a couple of boxes of hot commercial .308 Win. Now he will shoot premium ammo, the good stuff, just like the people he admires and wants to emulate.
Back at the range, he shoots some 7.62 NATO as a warm-up, and then turns to the .308 Win. The first shot produces noticeably greater recoil, flash and report. The experience is exciting, much like the first time he drove a friend's hot rod. He doesn't realize that this ammo is producing significantly higher pressure than even the defective mil-surp; after all, he "knows" it is the same as the 7.62 NATO he has already been shooting, just higher quality. He barely notices the fact that the bolt is now significantly stiffer in action. He shoots several more rounds. By round 15, even he notices the bolt's increasing stiffness of operation. But unaware of the significance, he continues to shoot. He doesn't notice the severely flattened primers, and wouldn't know what it meant if he did.
Round 17 produces a hissing noise, and a tiny plume of smoke around the bolt. The bolt is very difficult to operate, and he must exert himself to open the action and eject the cartridge. Although he doesn't notice the primer damage, even Joe is now concerned that something is wrong. In fact, the primer has blown out, and gas has escaped around the bolt head and around the firing pin into the bolt assembly itself. He decides to shoot just one more round, only to see if #17 was a fluke.
It is one round too many. The rifle has developed more headspace than the case can manage. The primer blows out again, white-hot gas at 55,000 psi escapes into the bolt assembly. Almost instantaneously, stretched beyond its limits, the case fails around the head. The white-hot gas also escapes around the bolt head and into the action. The meager provisions of the design for escaped gas management are overwhelmed. The bolt is fractured, and the firing pin and bolt sleeve are blown back into Joe's face. Simultaneously the gas enters the magazine well and blows the magazine and stock to smithereens, showering Joe with splinters and shrapnel and causing serious burns.
Outrageous, you say? Can't happen, you say? Well, it can happen and it has happened, perhaps not exactly as I describe above, but close enough not to matter. A regular contributor to the boards recently posted about the damage and injury that resulted from what was almost certainly a case failure. While that damage was caused by attempting to fire a cartridge that was grossly mismatched to the chamber, the damage was caused by exactly the same mechanism as one described above, that is, case failure. And it happened in a modern rifle, well known for the strength of its design, with modern escaped gas management technology.
For every regular contributor to these boards there is an unknown number of visitors who read but do not post. Many, I suspect, are not nearly as knowledgeable about the art and science of shooting and firearms as are many of us. We do them a disservice when we perpetuate potentially dangerous mythology.
By simply acknowledging the facts, and using the correct terminology ourselves, we may very well prevent harm. I love the shooting sports and I don't want to see anyone hurt engaging in them. I certainly don't want to provide fodder to the "antis" who continually try to portray our sport as unreasonably dangerous. I don't mean to offend anyone, but when people make reference to ".308 NATO", or make statements to the effect that the differences between .308 Win and 7.62 NATO are insignificant, they are promoting potentially dangerous misinformation.
redcedars
"The true art of war lies in so sapping your opponent's will to fight that he surrenders without battle." Sun Tzu
0
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I bought some of the 7.62 stuff at a gun show last week, is it safe to shoot in a modern .308 rifle? 0 -
"By the way, the thicker brass will raise pressures as this reduces case capacity, not the other way around as you have stated."
All other things being equal, thicker case wall = smaller case capacity = higher pressure. But that is not the situation, nor is it the issue. If you will re-read my post, I never said it was.
"I, along with most other shooters, have used and continue to use military surplus NATO ammo in bolt-action commercial rifles chambered for the .308 without harm or incident...
If you think it is unwise to use NATO ammo, then don't do it."
Once again, please re-read my post. I said I would not do so. I question whether "most" shooters do. But the problem I address is the opposite, that is, shooting .308 Win in an old bolt rifle originally designed and chambered for much lower operating pressure cartridges, but now re-chambered for 7.62 NATO. .308 Win approaches the original PROOF pressure for such rifles, and therefore this practice is essentially giving an old rifle a steady diet of proof loads. Its case dimensions are both thinner and smaller, so the potential is for excessive headspace with a cartridge even less able to tolerate the required degree of expansion than the 7.62 NATO.
"I suspect that any military rifle chambered in the NATO caliber is safe with mil-spec or commercially loaded ammo. I have not heard of any problems with the Enfields you mentioned."
I disagree, for the reasons previously stated. Are you really suggesting that a steady diet of near-proof pressure loads in a 50 - 100 year old rifle is a good idea? I am aware of reports of Ishapore Enfields developing excess headspace after shooting less than 50 rounds of .308 Win.
If you choose to rely on the representations of surplus rifle dealers who, giving them every benefit of doubt, don't even know the difference between .308 Win and 7.62 NATO, fine. These guys are insured.
I don't believe the sky is falling. It should be clear that I described a worst-case scenario for illustrative purposes. In the vast majority of cases, I believe the problems will result in an unshootable rifle, or one sufficiently difficult to shoot, that the catastrophic failure I describe is avoided. I am saying that it makes no sense to stand under the sword of Damoclese, and we should be careful that we do not contribute to others doing so unknowingly.
Because I don't want it to happen even once.
redcedars
"The true art of war lies in so sapping your opponent's will to fight that he surrenders without battle." Sun Tzu
Edited by - redcedars on 10/13/2002 14:39:53
Edited by - redcedars on 10/13/2002 14:42:170 -
Robert:
For a number of reasons, I would not do so. But I don't believe it is unsafe in the vast majority of cases. I am describing the problems associated with a different practice, that is, shooting .308 Win in an old bolt originally designed and chambered for a much lower operating pressure cartridge, and re-chambered to 7.62 NATO.
redcedars
"The true art of war lies in so sapping your opponent's will to fight that he surrenders without battle." Sun Tzu0 -
Redcedars,
Thanks for pointing this out; I recall the subject being discussed here before. I never knew the difference myself--I thought it was all just a "name difference".
I'm thinking, something which might be adding to the confusion about people thinking they are the "same", could be from the manuals of current firearm manufactures--don't most say something to the effect of "both 7.62 Nato and Winchester 308 ammunition can be used safely in (name the rifle)"?
Maybe you could send a "concise" letter to the current firearm manufactures, stating what you're saying here, suggesting that they include a "footnote" with their ammunition suggestions for their rifle which would note that there are slight differences between the rounds and that, while it is safe to use the rounds interchangably in their specific firearm, it MAY NOT BE SAFE to use the rounds interchangable in other firearms.
With the concern for safety most firearm manufactures demonstrate, I'm sure they appreciate your suggestions.
And thanks for pointing out this difference.
Joe0 -
Saxon Pig....X-Ring!!!Beach 0 -
The issue you raise is really one of speaking the truth plainly. Call things what they are. Use ammo designed for your gun. Don't get cheap on what amounts to a controlled explosive device. Eat, sleep and drink gun safety and don't hesitate to tell these principles to others.
It's ultimately up to the shooter to filter what he hears from others. Verify what you learn. "Is this really true?" Most people aren't as careful when they speak or write as they believe they are.
Three Precious Metals: Gold, silver and lead0 -
redcedars, The following is a quote from CARTRIDGES OF THE WORLD by Frank C. Barnes, third edition published in 1972. From page 37 describing the .308 Winchester cartridge.
"Introduced by Winchester as a new sporting cartridge in 1952, the .308 is nothing more than than the U.S. T-65 or the NATO 7.62X51mm military round."
If this "reluctance to admit differences" exists, it goes back at least 30 years.0 -
Regarding the Ishapore Enfields-
It was my understanding that the conversions of older, c.1940's to .308 are a bit iffy. Those made in the 60's (mine included) should be of higher quality steel. I don't remember where I heard this. I myself once didn't know the difference in these 2 rounds and fired 40 rounds of .308 in the 1966 2A1 with no flattened primers, no stiff extraction, etc. Then again it was cheap, FJM standard .308. I can see how you really could get into trouble firing some of the Light Magnum stuff. I have since switched to South African and Portuguese 7.62 Nato for the gun, though I suspect that if I fired the .308 till Kingdom come no harm would result. Remember, a lot of stupid amatueur gunsmiths once rebarreled Krags to 30-06; many of these conversions, weaker than any enfield, took it without complain though many suffered the common cracked lug.
Also, I think you are severely understimating the strength of modern brass. I have read that a quality case can take several tens of thousands of pounds of pressure, which in fact they regularly do when fired. I have had complete case head seperations in Arisakas and Mannlichers with loose chambers on occasion and in every case, the gun was fine. I have had spit primers using only hot Turk surplus 8mm and then rarely.
I am not arguing with you, just I think that you are a bit over-worried. Of all my milsurps, the Enfields are some of the guns I feel safest behind.
"...hit your enemy in the belly, and kick him when he is down, and boil his prisoners in oil- if you take any- and torture his women and children. Then people will keep clear of you..." -Admiral of the Fleet Lord Fisher, speaking at the Hague Peace Conf0
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