Tom McHale, risks a fight to explain the subtle nuances between 7.62 NATO vs .308 Winchester Ammunition.
If you want to start a good bar fight, ask a saloon full of gun people about the differences between .308 Winchester and 7.62x51mm NATO. We’re going to dive into the fray with a simplified and practical explanation. Ready?
- They are different.
- They aren’t different.
- They might be different.
OK, so that was a bit of a wise guy response, but those statements are all quite true. Don’t worry, we’ll explain it further. However, we’re going to try to do that in such a way that you don’t want to bash your own brains out by having to read about the nuances of things like piezo transducers.
Let’s look at a few categories of comparison, then we’ll sum things up.
7.62 NATO vs .308 Winchester – History
During the 1940s and early 1950s, military rocket surgeons wanted to improve the effectiveness of the M1 Garand rifle and its .30-06 cartridge. One contender, more suitable for higher capacity box magazines was a modified .300 Savage design called the T65. While specs varied throughout development, it ended up as the earliest iteration of the 7.62x51mm NATO. But, as usual, the commercial market was more nimble, and Winchester launched the .308 Winchester in 1952.
It took the government until 1957 to have a cartridge and rifle hitting the barracks with similar specs.
7.62 vs .308 – Pressure
Here’s where some of the confusion comes into the picture. Maximum pressure numbers thrown around for the two calibers are often shown as 50,000 “psi” for 7.62 and 62,000 psi for .308. At first glance, that appears to be a big difference and a potential reason why folks might consider it unsafe to fire a “higher pressure” commercial .308 cartridge in a rifle built for 7.62x51mm NATO.
As with most things, the devil is in the details. I put that 50,000 “psi” number in quotes because it’s wrong, at least when shown with a pounds per square inch label at the end. That 50,000 number is actually an accurate representation of copper units of pressure or CUP. A far less precise way to measure pressure, the method literally relies on looking at how much little copper disks compress when you fire the gun. While there isn’t a consistent mathematical formula that equates CUP to pounds per square inch (PSI) across the board, the difference in this specific case is somewhere around 8,000. In other words, the maximum pressure for 7.62x51mm NATO is about 58,000 psi – not all that far from the 62,000 figure for commercial .308 Winchester.
As both loads are routinely proof tested at far higher levels, this 4,000 isn’t a difference that’s going to alter the trajectory of Michael Moore’s daily Krispy Kreme run.
7.62 NATO vs .308 Win – Case thickness
Measuring the thickness of cartridge cases is kind of a pain, especially since I tend to mash them all up when trying to cut them in half with my Dremel tool. So, I took the shortcut to illustrate the difference. From my big bucket of .308 / 7.62 brass, I selected some representative samples of both commercial .308 Winchester and 7.62x51mm NATO brass and weighed them. I picked several of each and averaged the weights. I didn’t measure the cases because they’ve been fired, so that won’t tell me much other than the general size of the chamber from which they went bang.
- Hornady .308: 169.6 grains
- Winchester .308: 163.3 grains
- Lake City 7.62x51mm NATO: 183.5 grains
That’s a significant difference! Thicker walls combined with similar exterior dimensions means less powder capacity and a lower “top end” and all else the same, lower pressure and velocity.
The thicker brass of 7.62 cases is a significant factor for the reason we’ll discuss next.
7.62 NATO vs .308 Winchester – Headspace
Last but not least we get to the real difference. Military rifles for 7.62x51mm NATO can, and usually do, have longer chambers. In things like machine guns powered by ammo made all over the world, there’s got to be some slack for reliable feeding and operation with all that violence going on during the feeding and ejection process. The solution is to make the chamber headspace a bit longer. If you’re not familiar with headspace, think of it as the distance from the bolt face to the point in the chamber that stops the forward motion of the cartridge case. If the chamber headspace is too long for a cartridge, it will float back and forth in the chamber. If the headspace is too small, the bolt will not close properly or will require excess force to close.
How much different is the headspace? The .308 Winchester chamber headspace is between 1.630 and 1.6340 inches (SAAMI Info). The 7.62x51mm NATO is between 1.6355 and 1.6405 inches. While the published numbers show about six-thousandths of an inch difference, it’s not unusual for the headspace in a surplus 7.62 rifle to be 10 or even 15 thousandths longer than that of a commercial .308. That doesn’t sound like a big deal, right up to the point where you fire thinner commercial brass in a long-chambered rifle. The brass will stretch, possibly enough to contribute to a dangerous case rupture. Doing the same thing with thicker military brass is no big deal and the way the system was designed. Thicker brass can handle some extra stretching into a longer chamber throat, so it’s no big deal.
The solution to the question is to know your rifle and what its headspace really is. Only then will you know if it is safe to shoot commercial .308 Winchester ammo in a 7.62 chamber.
Figuring out if your headspace is safe is a fairly straightforward deal. You can order a set of .308 Winchester Go / No-Go headspace gauges. After removing extractors and/or ejectors as appropriate in order to remove all sources of tension, use the gauges to check the chamber size. The bolt should close easily on a Go gauge and not close on a No-Go gauge. A third type, a Field Gauge checks the maximum published chamber size. With some 7.62 rifles, you might find that the bolt closes on the No-Go gauge. As long as the bolt won’t close on the Field gauge, you’re still within maximum published limits.
The net-net-net
Technically speaking, in terms of specifications, there are differences, but mainly in the chambers of rifles designed to fire each cartridge. 7.62 brass is a bit thicker, and commercial .308 is sometimes loaded to slightly higher pressure, but other than that, the cartridges themselves are pretty much the same.
If you want to be ultra-safe and conservative, fire only 7.62x51m NATO in 7.62 chambered rifles and .308 Winchester in .308 rifles.
Next on the “risk” spectrum is the scenarios of using 7.62x51mm NATO ammo in a .308 chamber. In theory, you might run across ammo that’s particularly long. Ammo might not chamber at all or might require undue pressure to the chamber. That could result in dangerously high pressure. In reality, that would be really unusual. While 7.62 ammo could be significantly longer, that’s a pretty rare thing, at least to a significant level, so most people don’t consider it a big deal to use 7.62 ammo in a .308 chambered rifle.
Where you need to be careful is using .308 Winchester commercial ammo in a 7.62x51mm NATO chambered rifle.
While most modern 7.62 chambers are probably fine as they tend to be cut closer to .308 dimensions, it’s always safest to know exactly what you have in terms of headspace. If your rifle has long headspace, stick to 7.62 NATO ammo – don’t use commercial .308.
About
Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon. You can also find him on Google+, Facebook, Twitter and Pinterest.
Tom McHale
I doubt you will see this but I wanted to thank you for this article. The information you provided and the dialogue you provoked was extremely informative. Best wishes and thank you. Stevan
I have long wondered about the so-called “catastrophic failure” claim given to incipient stretching, and ultimately separation, of the side walls of a cartridge case due to excess head space. I have noticed that, in some cases, high power rifle cartridges such as 30-06 have been (and sometimes still are) made with a plastic body separating a brass head and a brass neck. The only really strong part of a case is the head, which seals the breech, while the rest of the case is pretty much just a weak powder container. I have fired some old WWII cartridges that… Read more »
There are a number of artillery/tank rounds that use a short base section to contain the primer and seal the breach end of the tube.
My experiences are similar. I’ve had a number of cases split the neck, and didn’t even have sticky extraction. In fact, that is how most of my cases eventually fail. I don’t even know it most of the time, until I inspect them after tumbling. But I have fixed a few firearms that, for various reasons, separated completely at the base, leaving the body of the case stuck in the chamber. Including a few that blew the muzzle blast directly backward into the bolt, which directed it downward, shattering the stock in the magazine area into toothpicks! So catastrophic case… Read more »
Interesting and informative. Thanks!
This is one of the most helpful articles to me that describes both the practical theory of the .308 v 7.62 NATO rounds, plus the meaning of headspace and how it relates to guns and ammunition. I had never really understood exactly what headspace was and how to measure it, or why it was so important. Now, I can both understand it and apply it to my own guns. I have a 1916 Spanish Mauser that has been converted to .308 Winchester, purchased from Classic Firearms some time ago. I have finished fixing it up cosmetically and have installed a… Read more »
An important aspect that you didn’t touch on is handloading. I would hope that anyone who “rolls their own” would be savvy to the difference in brass, and sorts their brass carefully. Throw your favorite hot .308 powder charge into a 7.62 case and you’re cruising for a rude surprise.
But not if you work up to that hot load in whatever case you choose. Military or commercial. Taking a max load and switching out to a different case (even if both are commercial cases, but just different brand names) is just asking for trouble. The only component that one might be able to swap out is the primers, but I work up again even at that. For semi autos, I just stay under max and do them in mass on a progressive press. If I want max performance out of one then I go back to working up loads… Read more »
Have you tried small rifle primer cases? I don’t know if they have them in 308 yet but if they do they might make a difference in 308 like they do in 6.5 Creedmoor.
Over my life I have done many esoteric things in the reloading realm. One of those things is working out how to use small rifle and small pistol primers in large rifle cases. You can do this by taking the anvil out of a fired large pistol primer and flattening the firing pin indentation in the LP cup. Then place the SP/SR primer in the cup and seat in the large rifle primer pocket. Of course you will have to adjust your load but that set up will handle normal rifle pressure levels. Just thought I would pass it along.… Read more »
I think Starline makes 308 cases with small rifle primer and large rifle primers, but I haven’t checked on that. I was just wondering if anyone has tried them.
The only larger capacity cases with small primer pockets that I’ve worked with was the 6mm PPC round. I did benchrest shooting for a little while, but switched to IPSC instead. The minute details of benchresting just weren’t as exciting for me as competion with more action. I still like long range shooting though, but not down to such an extreme degree as benchresting. I prefer larger targets at extreme range, instead of shooting tiny groups at close range. The most esoteric thing I’ve done in reloading is making my own .45 ACP cases from .308 rifle brass, and shooting… Read more »
Soooo, if it is a relatively NEW manufactured weapon it should be safe to say that it has been and is more than likely chambered for use with both the 7.62 NATO and the .308 Winchester. Battlefield “pickups” or old surplus ammo should be checked and verified before mixing the ammo. Right ?
As always, thanks for an excellent piece, Tom. And a belated contrats on the editorship at AH.
Paul Valone
President, Grass Roots North Carolina
Answers a lot of questions for me, basically if it’s a bolt let her fly. Wonder if there are any differences in 30-06 military rounds and off the shelf ? Pressure wise ? Just guessing newer rounds would be higher pressures.
Beginning of the article had me thinking I need to get my rot eggs that I’m saving for the next antifa suppression strike.I put em away.very good article! Kind of makes me thing of garand when he designed the m1 for the. 276 petterson round only to be told by some Indian war Era remf that they wanted it in 06 because of all the ww1 leftovers.
WHAT ???
When I got my Remington 700 5R, chambered in .308, a few years ago, I was getting ready to buy some ammo. I found some 175 grain .308 Federal Gold Medal Match at a good price and, I bought some. Shortly afterward, I found some 175 grain 7.62×51 Federal Gold Medal Match ammo on sale. According to the information on the boxes, both had the same specs. So, I emailed Federal and asked them what was different about them. They responded that the 7.62 cases were not polished, like the .308, because military specs require the cases to be “visibly… Read more »
When using ammunition hand loaded to higher .308 performance specs, I find that there is somewhat more violent cycling in some .308 semi-autos, with cases not infrequently blowing out their primers and the extractor leaving a deep dent in the case rim. This harsh activity can be tamed somewhat by fine-tuning the firearm, but a less strongly charged 7.62×51 load more immediately cycles the action in a comfortable way and is less damaging to the brass. Therefore, when using a semi-auto .308, I find it most practical to stick with slightly lighter charges, more at the power of a 7.62×51… Read more »
What’s the difference between .308 Winchester and 7.62 x 51 MM NATO cartridges. Chamber pressure and small but interesting dimensional differences. Take a careful look at standard cartridge drawings, paying particular attention to demensional differences.
I’ve recently purchased a Springfield M1A and their included manual states the rifle will fire either .308 or 7.62 as long as it is quality factory ammo manufactured to SAAMI/NATO standards.
In that case, what are the benefits/trade-offs between the two calibers? Price? Accuracy? Availability? Why should I chose one over the other for my M1A?
*I’ve purchased the scout/squad variant – I do not intend it be a long range/precision engagement rifle. Moderate range consistency/reliability are my priorities.
Try to stay away from the cheap (especially the steel cased) 7.62, as it is not always within tolerances. If you wish to use surplus, stay with Israeli ROK or US surplus, which will be within NATO specs. It won’t be as accurate as the commercial ammunition. But it will be noticeably cheaper which may make it desirable as practice ammo. Commercial ammo is generally more accurate than the surplus ammunition due to the commercial manufacturers’ closer accuracy requirements. Remember, most milspec ammo is designed to have about a 3″ dispersion from a test barrel at 100 meters, because it… Read more »
Match Ammunition, if you can find any, was usually quite accurate, though there were lot to lot and rifle to rifle variations. Also, primers were not crimped, saving a bothersome operation for those who reload.
You won’t notice much difference between both rounds. Military 7.62 rounds will probably have a bit more ass to them and hit the target harder. Military 7.62 NATO ammo used to sell for $0.015 per round back in better days. Now it’s 3 times more when you can find it, but still cheaper than commercial ammo. I like my reload for training and play or compition, I’ve got 20 mags loaded with 4 A.P. 1 Traser, the standard military load out except I use A.P. instead of ball ammo. I also keep 5 mags loaded with tracker for nights. This… Read more »
Firing real Match grade ammo in a service or combat rifle is a waste of money. You won’t notice the difference. Match ammo is designed to be used in a Match rifle. The two together will produce the desired result. Used speratly not so much. From a long time CMP shooting I’ve seen a lot of this with less than satisfactory results
I think that depends on the service rifle. I have both M1s from the CMP and a 1903A3. I have shot match grade ammunition and service grade ammunition in both of them, and group sizes with match grade ammunition tends to be 1/2 or less the size of service grade ammunition. I also have a civilian HK91, which is an original from around 1975. It also likes match grade ammunition much better than service grade, and I shoot both .308 Winchester and 7.62 X 51mm NATO in it. It feeds and cycles all that I’ve fed it except some poorly… Read more »
The difference between the .308 Winchester ammunition and the 7.62 × 57mm ammunition is the brass The military round has a thicker case head and have a crimped primer and thicker shoulder and neck. It’s made to survive military combat as well as for both rifle and machine gun use. And is sealed against weather and water damage.As a result the interior of the case has a smaller diameter and will hold less power than a .308 Winchester case. Also keep in mind that 7.62 NATO ammunition is manufactured with both boxer and burdan primers. Some of the military brass… Read more »
Mr. Furbush, you are correct on all counts as far as I can tell, except for the 7.62 typo. And I really dislike Burdan primed brass. The military brass like Lake City was designed for machine guns, so it was made thicker at the casehead and the web. It is designed to withstand being chambered and extracted by bolts and bolt carriers which exert more force than a semi-automatic rifle, and the primer crimp is done for the same reason. No machine gun crew can afford malfunctions due to head separation or failure to extract or a loose primed jamming… Read more »
You’re correct good sir typo 7.62X51mm. I’ve noticed a small difference in accuracy in my 03A3 with match 06 ammo. Most M1 and M14 service grade rifles won’t show much with G.I. match rounds. I was a Recon Marine scout sniper. I ended up in STA PLATOON in GW1 The 2 weapons I was issued at the time the M40A1 for day and the M25 with a suppressor and night scope. For night work. I actually preferred the M25 for both. The M40A1 is a fine weapon and I have my own that I built myself. I also have my… Read more »
Sorry to hear about your son, sir. May God grant that you both meet at Jesus’ feet in the time to come. God bless you and yours and deep and abiding thanks for your service and sacrifices. Your fellow soldier:
Elton P. Green, SSG. USA. Inf., (Ret.)
I just bought a PSA PA-10 and it says 308 on the barrel. That’s great except I reload and I buy once fired 7.62×51 brass that has been cleaned, resized, and primmer pockets reamed. I’m assuming that reloading them to 308 spec’s should work?
On January 28, 1986, the NASA shuttle orbiter mission STS-51-L and the tenth flight of Space Shuttle Challenger broke apart 73 seconds into its flight, killing all seven crew members.
I’m relation, that space shuttle, “should have worked”? Then again if you want to buy a brand new Mercedes then run to Wal-Mart and swap out the tires, for whatever I’m-godly reason? Have at it! Personally? I would rather spend the extra 12 cents per round that you might be saving and buy factory fresh ammo. But hey? I’m funny that way!
Gregory, you are under the misconception of why most folks reload their own ammo. It has nothing to do with saving .12 cents but more about tailoring a load to a specific firearm. Admittedly factory ammunition has gotten very good in the last few years but generally will not shoot to the level of a properly constructed handload in most rifles. So for those folks that are seeking the ultimate performance from their rifle, handloading is the only real option.
After sizing the brass, the 7.62 will still have thicker walls, meaning less space for powder to expand, meaning potentially greater pressures. Unless you have the tools and safety equipment necessary for measuring pressure, I’d recommend using the ammo marked on the barrel.
In reloading military brass, which is thicker walled than commercial brass, use the Starting Load in whichever manual you fancy, and work up SLOWLY from there, say 0.5 grain increments..
I forgot one thing about milspec brass (or any .308/7.62X51 brass) when re-sizing. Don’t full-length size it so far down that you set the shoulder back. If you are sizing it for a bolt action rifle, size it just enough to get a tight fit in the chamber. That’s what is called a ‘crush fit’. If you are going to shoot it in a semi automatic, size it to fit slightly snug (very slightly snug). There should be a very slight resistance when manually closing the bolt, but complete lock up. If you size it too far down the casing,… Read more »
Ignore Mr. Romeu. The answer is yes. But remember to stay on the low side and work up. The brass is thicker so pressures rise a little quicker. Your rifle is rated for 62,000 PSI. Stay at about 56,000 PSI or 47,000 CUP and you’re all right when using the .308 data. Start about 10% below the maximum load in the load manual and work up. Check your brass for signs of scuffing on the face, and primer flattening. Measure each of your test cases with a caliper and compare them with once fired commercial brass. Work up in half… Read more »
Elton P Green, thank you for replies and your service. Helping us who have legitimate questions in a respectful and professional manner is much appreciated.
I hope this did help you. If you get a Speer or Lee reloading manual, either one (Both is a good idea) will give you step by step instructions for working up safe loads. And you’re welcome. I’d serve again tomorrow if they’d let me.
Thank you for your valuable advice. I appreciate your respectful and kind reply as well. Reading your kind of comments is one way for others to learn rather than be frustrated and turned away having learned nothing. Additionally, I thank you for your service to our country, sir.
I found Lyman manuals useful too. As a general comment, whichever manual or manuals strike your fancy, spend some time reading them BEFORE actually reloading. By the way, I used once fired LC Match Brass picked up at Quantico. No fired brass left on the firing lines. Fired brass went into cans behind the firing line, or into whatever bag or container civilian shooters like myself brought. I never found the use of small base dies necessary. As by then, I was shooting bolt action rifles, Match Brass that had been fired once in Match Grade M-14’s used by Marine… Read more »
Alan, Lyman loading manuals are very good. One of the things I like about them is that they aren’t proprietary because Lyman doesn’t produce either the powders or the bullets used. I currently use their cast bullet reloading manual.
SSG Elton P. Green USA Inf. (ret.)
What about bolt action rifles? Savage 308. Can it handle a 7.62?
Yes, but not accurately. I have an older savage 110 in 308. The bolt is tighter with certain rounds, and fine with others. (Same batch, Norinco 7.62×51) My savage was very picky with ammo to get MOA accuracy. Only one so far is Barnes TTSX 168. With the Norinco ammo, it fires safely, had one split neck out of 100 rounds. But asides from controlling trigger flinch, it isn’t much use. At 100 yards, I can barely hit a 14″ target. I am going to try brass Mil Surp from Austria this weekend. But considering all millsurp is lighter projectiles,… Read more »
The quick answer to that is no. The 147 grain boat tail has a much lower Ballistic Coefficient. As a result, it has a poorer trajectory at distance. The 165 grain boat tail has a much higher B.C. and the 167 and 168 grain match bullets have B.C.’s in the range of .480 or so. Trajectory at distance is much flatter. More importantly, wind drift is noticeably less. What the match grade round loses in initial velocity it gains in retained velocity down-range. Accuracy is another issue, but it depends on the manufacturer, lot # of the ammunition, and whether… Read more »
I’m going to correct part of my April 12, 2018 answer. The answer is actually yes and no (but more no than yes). At ranges out to about 500 yards (more or less) the 147 grain round will have a fairly close trajectory to the .308 Win. match 168 grain ammunition. Accuracy will be notably poorer as noted in the original comment, unless you get a lot number that was manufactured to closer tolerances, which can happen. For instance, when a sniper didn’t have Lake City Match ammo, he was instructed by the manual to test various lots of ammunition… Read more »
Yup. Bolt guns will run with any safe load as long as you’re rifle doesn’t have head space issues. If you’re using new brass you only have to neck size it. It will fire form to the rifles chamber. Of you want to use once fired military brass you’ll need to fill length resize it for the first load and neck size for the rest. You’ll probably get 10 to 12 loads out of each case. I’ve actually gotten more
You’re fine with military brass. It’s a bit more work but often can be had at cheeper price. The exterior dimensions are the same. You’ll find the military brass won’t hold as much powder because the brass is thicker. This makes the interior smaller. It’s not really an issue unless you’re trying to get a maximum load of some type. Make sure you resize you’re brass properly. A little extra case lube a run it through the die 4 times turing it a quarter turn each time if you’re using it in a gas gun. In a bolt gun it’s… Read more »
Unlike some here, I will actually answer your (very reasonable) question. Yes, they will work. The external dimensions of the brass are EXACTLY the same as .308 Winchester. As a matter of fact, Winchester copied the round so that they could introduce it as a commercial round. The differences are in the case wall thickness and the case web thickness at the case head. Because the brass is thicker it has a quicker pressure curve, though. You need to start at least 3 grains under the maximum charge for a .308 Winchester load and work up from there. Because it… Read more »
Again, I’ll answer your question instead of implying you are an idiot, which you are not. I also reload military once-fired brass. If its been resized to .308 Win dimensions, it should be fine. (308 Win, and US 7.62X51 have exactly the same outside dimensions, as Winchester just copied the military round.) Just chamber some empty brass in your rifle first. This will tell you if it fits the chamber because if the bolt will lock up, its sized correctly. Then reload it normally, working up from an 85% charge of your favorite powder, projectile and primer, 5 or 10… Read more »
The logic, and science behind the non-interchangeability of .223 Remington and 5.56 NATO is profound and based on experience and extensive testing over many years indicating a viable concern, including actual catastrophic failures due solely to the lack of interchangeability. The claim that the same applies to .308 Winchester vs. 7.62 NATO is speculative and theoretical at best. We have more examples over a far greater period of time of the successful interchanging between .308 with 7.62, and vice versa, and are continuing to do so, without any dangerous or injurious results, than we have had with .223 vs 5.56… Read more »
It might be useful for shooters to know that a .308 AR-10 (semi-auto in action) should normally be tuned to fire M80 military rounds, at least in my experience. Such a rifle may not cycle properly if one fires higher pressured rounds. Also, it may pop out primers and also shear the extraction rim of the brass. I believe this observed problem is largely because the brass, when pressed more tightly to the chamber wall by higher pressure of a Win .308 loading, may not be ready to release freely at the moment that the bolt pulls back to extract… Read more »
The .308 case holds more powder than the 7.62X51. I separate my brass and load different bullets in each. I also use one load for my .308’s and one load for my M1A NM since each will have a different point of impact. By doing this I do not have to keep re-adjusting my scopes to handle different loads.
I load both 308 cases and 7.62×51 cases for my Palmetto AR10 and Ruger American 308 bolt rifle . Both work just fine with the same powder charge and bullet weight . The AR 10 cycles perfect and the cases have zero dents from extraction . The bolt rifle cycles both cases well also without any issues also .
This aligns with what I’ve heard: The main concern is .308 in early conversions of older rifles to 7.62 like the various Kar98 conversions. Modern stuff shouldn’t be an issue.
.308 Win. is top dog in that match up!
A lot of names on this old article that I don’t see anymore and one in particular has a photo and a different name than I am used to seeing associated with it. Hum!!!!!!
Music, 3,4,5,and six year old comments? Several years ago Knute Knute was just one Knute! USMC changed his handle too.
I thought USMC was a change.
Wish you had that radio. Today is a world wide contest. I have contacted, Sweden, Germany, Bulgaria, Croatia, Finland, Greenland, France, Italy and more. This is what it could be like if the systems went down.
It is interesting to hear people in other countries talk politics. Today, a man in Germany was saying that O’biden is trying to drag them into the Israeli war and they don’t want to get involved.
In the words of Colonel Klink. Very interesting!
I have not heard them on the air and I am heading to the reloading room. Just got 1,500 38cal Hornady FP and 8lbs of 300 MP. Want to load up a few and then go test them through the chrono later in the week. I am supposed to get 1,500 fps with my 8 inch colt.
I had experience that is different from this post and comments. I was shooting South African NATO 7.62×51 in my M1A. A young man with a Remington 700 in 308 asked if he could try my ammo in his rifle. The round chambered but when he fired the report was unusually loud. His bolt was frozen. He used a section of 2×4 to turn and beat the bolt open. The cast was stuck and diden’t eject. He left with case stuck in chamber. The other 3999 rounds (four crates) of South African ammo behaved without issue in my M1A. Any… Read more »
They’re basically the same…
One will kill you, and the other, will kill you too, so…
My specific experience has been that, when I load either 7.62x51mm NATO or .308 Win cartridges up to levels that manuals allow for .308 Win, I find that an AR-10, even with carefully adjusted gas flow, tends not to cycle well. This also happens when I use lower pressures of load but with fairly fast burning powder, which is more jarring in its action. For example, IMR 3031 doesn’t cycle reliably, often ejecting the empty case partially or fully, but failing to load the next round, in my particular experience, while IMR 4350 or Varget work reliably and smoothly. If… Read more »
Excellent article. Thanks for taking the time to explain this in detail. I take from the article that the most critical difference is the rifle headspace. I have a Scar 17S, and I wonder if it would be absolutely the same to fire 7.62x51mm or .308 taking into account the Scar 17S headspace. Thanks.
Bought my M1A from a gun-shop in NH. Salesman was an enthusiast who had an issue with the rifle that permanently scarred his face. This issue may have been part of it. I had never really understood what had happened to him or how to take steps to avoid it. Had seen the 14’s on armory detail in Parris Island when I was carrying a 16, had always liked the appearance, weight and once I owned a civilian model the way it feels and fires. Nice article I will have to see what my rifle is actually chambered for now,… Read more »
$973.90 for The paperback edition of The Rookie’s Guide to Guns and Shooting? I don’t think I’ll be buying that one.
Jay, not sure where you saw that price, but the link in the “About Tom McHale” has a list price of $9.95.
Your article begs the question, is it possible to design to accept either cartridge, same as done with .223/5.56?
Yes. A rifle rated to use .308 Win is typically considered fine to use with 7.62×51. This rule of thumb is extremely common, and most .308 Win rifle manufacturers say as much. I would simply be a little more cautious if using a rifle made for 7.62×51 but not for .308 Win. This is very similar to the .223/5.56 issue, but reversed, in that, with .308 Win, it is the commercial load, not the military load, that has the higher pressure.
I have a TC Dimension that is picky about the brass it uses. I have tried military brass and it won’t chamber it, even after running it through a small base sizer.
Why didnt you buy some reloading brass and measure them? And then load them withithout powder to proper cartridge specs for length by the squisher, and then drill out the fake bullet used?
Speaking of left-hand rifles…
After 50 years of fighting with right-hand weapons (I entered the Marine Corps in 1968), I just purchased a CZ Model 557, 30-06, LEFT-HAND!!!
I should have done this YEARS ago… Though selection was not that great.
The CZ is a fine weapon… Balanced, and just feels good in the hand. The fact that’s it gorgeous too doesn’t hurt.
Just thought I’d pass that on.
All the best gentlemen.
Richard Ard: As I too shot rifles left handed, being left eye dominant, found your comment interesting. I shot National,Match Course type competition for many years, first with a Garand, later on with bolt actions, mostly Model 70 Target Rifles. I used to get the occasional odd look shooting my Garand, especially respecting the rapid fire stages. Never had any trouble reloading with the Garand nor with Model 70’s, using stripper clips. I understand that CZ rifles are quite good, though I have no experience with them. As I expect you know, Savage has made their 110 series rifles in… Read more »
I found the biggest issue for using reloaded 7.62 cases in a 308 is that the brass, being thicker, requires neck-turning, not just resizing, to allow it to be fed in a rifle with a close-tolerance chamber without binding and causing pressure-spikes.
Gregory was very helpful on providing you all on some facts and figures that took some time to research. I appreciate the time and effort it took. There is always gonna be several out there that do not agree on your views and research, Why i dont know, like viper said use the ammo that is recommended for that weapon and be safe brothers. army vet.
Gregory Romeu, you seem to be a “internet troll” that pounces on anyone and anything that can make you feel smart in your own eyes, I’m here to help you, you are being a jerk, your life is missing something don’t sit at home and worship yourself. Back away from the computer and go look in the mirror. We hate your attitude here. Please try to educate yourself in basic kindness, maybe read the Bible. We would gladly welcome you if you would try to be a bit nicer. You do have a good heart inside you, feed it please.… Read more »
Obviously you have no understanding or idea as to what a TROLL actually is? Me? Not are troll by any means, I just loathe ignorance and stupidity, especially when the ANSWERS are bore right into the barrels of the firearms these people are in posession of. If you took the time to read deep into the text of those I responded to you would find most should not possess a firearm.
There is no place for niceties once a trigger is pulled. And you with a name like, “Cracker”?
Good read but one big mistake. All else being equal a thicker case will have higher pressure. Less volume and the same amount of powder equals higher pressure.
Buy wouldn’t a 308 case with a heavier bullet, with more powder to achieve longer and more effective ballistic performance generate higher pressures?
Good read but there’s a critical mistake. All else being the same, a thicker case will generate a higher pressure. A smaller volume with the equal amount of powder equals higher pressure. Is a standard .308 a compressed load? That would depend on the powder density and I’m sure all .308 are not compressed. From Berger on COAL and Bullet seating depth. “The primary effect of loading a cartridge long is that it leaves more internal volume inside the cartridge. This extra internal volume has a well-known effect; for a given powder charge, there will be less pressure and less… Read more »
The only thing I can say is that you may be overlooking quite a bit in that little phrase “all else being the same”. Most hand loading data from Hornady, Nosler, and Winchester state that there are two different sets of loads, one for .308 and one for 7.62, and the reason given is the lesser room inside the 7.62. There is no doubt at all that 7.62 is done to a slightly lower pressure. It is not “same powder”.
You didn’t read what I wrote, I know 7.62 and .308 are different in nearly the same way as .223 and 5.56 are, except 5.56 is the one with higher pressure. Quote from article “Thicker walls combined with similar exterior dimensions means less powder capacity and a lower “top end” and all else the same, lower pressure and velocity.” This is incorrect, misleading and possibly dangerous. A smaller case all else being the same, i.e. a .308 load in a Lake City 7.62 case vs. a .308 case, with the same bullet, same weight and type of powder, same primer… Read more »
Well, you are entirely entitled to your understanding of my reply. But I quoted you. My statement is concerned with your insistence that you would use the same powder charge on the 7.62 as you would .308. IF you did this, the pressure would be higher, yes. BUT loading specs from Hornady and the like state NOT to do this.
Mr. Lando is correct. If you are using the same powder in both casings (ie: Nosler 308 Win. and Lake City Match, for example) the Lake City brass will have a higher mean pressure when charged with the same type and amount of powder as the Nosler commercial casing. Also, this is true whether the load is compressed or if there is some space inside the cartridge. Also, some of the powders used in military (US) 7.62 are: IMR 4895, IMR 3031, Winchester 748, H4895 and currently, IMR4064. This is just a list of a few of the powders used… Read more »
Viper, is right shoot what’s on the barrel !!
Stop trying to ne ballistic GURU’S!
Capt Ed McCourt USMC(ret)
OOH RAH, Skipper!
Windham Weaponry SRC R16SFST-308
Semi Automatic Rifle
.308 Winchester and Accepts 7.62mm NATO
16.5″ Medium Profile Barrel
4150m Chrome Moly Vanadium 11595E Steel Barrel
I am looking at this rifle..you will note it says it will accept 7.62 NATO ammo is it safe to fire it then.
From the article a bove you seem to say so. Being that I have served and can get NATO 7.62 I would like a definite answer, if you please
Tim, 1) A blind monkey smoking a crack-pipe can get 7.62 NATO ammo. 2) If you served, in WHAT did you serve? And if so, then WHY didn’t teach you to put into the weapon that which is marked on the weapon? You wouldn’t put a,5.56 ball round in that chamber, would you? In other words, if it SAYS “7.62 NATO” on the barrel, then OBVIOUSLY you would use, “7.62 NATO” ammo.
Now, go ahead and explain to us all the special privledges YOU have in getting 7.62 NATO ammo, just because you served?
@Gregory Romeu
Jesus, you are a DICK!!!!! Tim was just asking a question. No reason to be a spiteful prick about it!!!
It’s people like YOU that are ruining the world for the “good people”!!!!
Ken? Back away from the computer and get off the internet before your mother catches you.
Yeah, if you could get a good price on those, I’ll take 50 cases please
Gregory… Perhaps he is not in the US? Maybe he lives in the EU or somewhere else where firearms and ammo are severely restricted… Every think about that possibility genius?
Gregory.
let me ask you a question.
i have a FN/FAL in 7.62 nato and that’s what i shoot in it.
but i also have a Savage Model 99 that says 308 caliber.
so i’m assuming i wouldn’t be able to shoot the 7.62 in my Savage due to the chamber not being as long as my FN/FAL.
is this right?
and thanks for any answer.
and i served as a Marine from 1960 to 1971.
and yes, a Vietnam vet.
Siempre Fi brother. 76 to 98 for me. Retired at E7. Either round will work in both of you’re rifles
i know it’s bee awhile lol.
but thatns for the ansrew.
Semper Fi.
James, Mr. Furbush is correct. Your Savage 99 will shoot either round, as long as the 7.62X51 NATO is of good manufacture. A check for this is to chamber the 7.62 round. Since your rifle is not a semi-automatic, you can perform a function check and if the round chambers and the action locks up properly, it will shoot the ammunition. And thank you for your service, sir. I am glad you got out alive. May God Bless you for a job well done.
SSG Elton P. Green, US Army Infantry, (Ret.)
The only definitive answer is to have a professional gunsmith determine the exact head space of the rifle. As mentioned in the article, a rifle that is chambered for .308 tends to have a headspace that is tighter, and here you want to think smaller. A rifle that has been chambered for 7.62 USUALLY has a longer headspace due to the multitude of different factories making this ammo around the world. The 7.62 NATO round has a thicker wall and is made to have a lower pressure. .308 is made with a thinner wall and higher pressure. So, sometimes when… Read more »
TheFixer is correct as to the information on the 7.62X51 NATO round. He is also correct about getting your rifle’s headspace checked. If the rifle is headspaced correctly, and the ammunition is within Army Ordinance specifications, you can shoot it in the rifle. A way to check the ammunition for proper specs is to hand-chamber it in your rifle and check to see that the bolt has gone completely into battery. If it has. the round should be safe to fire. But you have an expensive rifle. I wouldn’t use cheap surplus ammo in it just because it will work… Read more »
Tim, from one vet to another, yes you can use both. The rounds are supposed to be interchangeable. You will want to be careful with the country the ammunition comes from, though. Some countries have poor to no quality control, thus their ammunition is not made to Nato specs. Stay with IMI or Western European ammunition, notably British, German, Austrian Polish and Belgian surplus. These countries have good quality control procedures in place. Don’t buy anything loaded before about 1980. Also, check it to ensure it will chamber properly in your rifle. If it won’t, break it down, dump the… Read more »
Ignore Mr. Romeu’s comment. It is safe to fire NATO ammo in the SRC. Just make sure that you use ammunition from good sources, like IMI, British Radway Green, or German ammunition or US sources. Their ammunition is inspected and kept within close tolerances. Don’t use Chinese or Russian ammunition. It tends to be out of specs and can be really bad for your weapon. Different lots can be too long, too short, or just poorly made. Stay away from the steel cased ammo, too. Cliff’s experience with Norinco ammunition is not unusual. It is poorly made and quality control… Read more »
Myself, I would be wary of using spent .308 brass for reloading purposes unless I knew exactly what rifle it had been fired through prior to ending up on the range floor. The stretch of .308 brass fired through unknown 7.62×51 chambers could result in empties that -might- head separate without warning due to the “headspace stretch” -ALL- occurring at the base end of the case and NOT at the shoulder/body length area (which would happen in carefully fireformed brass). All those reloading articles explaining when to discard rifle cases due to the displacement of brass from the base area… Read more »
I’ve read lots of articles on this subject. And I like to ask the same question and see how many different answers I get from each article. OK here it goes-I have an M1A loaded with .308NM (National Match) stamped on the barrel. So what can I shoot? Some people say of course you can use both and some people say .308 is too hard on the auto loading mechanism, it’s strictly for bolt action. Some people say since it’s stamped .308 on the barrel it’s chambered for .308 and that ammo works better in that rifle. Now I’ve only… Read more »
The simple answer here is that the BARREL is marked .308NM. It means that the barrel has been made to a certain degree of accuracy. It does NOT mean that you can or should change calibers to the 7.62 NATO. It’s still a .308, man. You really want to jam 7.62 into what must be a fairly expensive barrel to start? Even if you get the round to cycle, please think of what you are doing to the chambering. M1A NM means that has been set up for .308 target shooting or sniper activity. If you have an M1A that… Read more »
WYF Is your problem? Military weapons issued to troops in military service are fed issue ammunition. The military caliber is marked on the barrel so the correct ammunition is issued and loaded into the weapon. Shooting 5.56mm rounds in an AR15 rifle will do no harm to that rifle provided it was assembled correctly. I’ve been doing this for a long time with both factory and rifles I’ve put together out of military spec. Parts. Same thing with 7.62 NATO and .308 Winchester. The simple difference is military brass is thicker so less room inside the case. The exterior dimensions… Read more »
Ignore Mr. Romeu. If it says it will accept both, it will accept both. If you are really concerned, call Windham Weaponry and confirm. And thank you for your service.
Elton Green, SSG, USA Inf., Ret.
The NM barrel for the M1A has a match chamber, which is on the tight side of the chamber tolerance for the .308 Win. cartridge. It will fire 7.62X51 safely if it can chamber the ammunition. In other words, if the ammunition is within US Military Ordinance Department specifications. If you buy surplus ammunition, check it to insure it will chamber properly. If the bolt won’t lock up, the ammo is out of spec. Disassemble it and re-size the brass for reloading. If it will chamber properly, it will be safe to fire. Again, the two cartridges have EXACTLY the… Read more »
Hey JD you’re rifle is a fine target rifle. You’re best results will be with commercial .308 Winchester ammunition. You’re rate if rifling twist is 1:10. This will stabilize up to 175 grain match bullets very well. You can also shoot 150 grain loads for the shorter range matches. Out to 200 yds. They work well. The 175gr. Load works best at 500 and 600 yards. It goes to sleep at around 350 yards and is still over 1000 fps at 800 yds. This is why the Marine Corps and the Army switched back from the 168gr. Bullet. The 168gr… Read more »
A National Match M1A is an M1A designed from the ground up for accuracy. It has a precision trigger, precision sights, national match bolt, operating rod, gas system, barrel and flash suppressor. The chamber and barrel are bored and rifled to very close tolerances, the barrel is generally gaged to be within around .0005 from breech to bore, and the stock and hand guard are hand fitted to exacting tolerances to insure proper bedding of the action and barrel. The NM designation is the proof that all this has been done to the rifle and that the rifle should meet… Read more »
I made the mistake of shooting 308 commercial brass which I reload in my m14 I have a R.E.M. 7600 in 308 so I used same loads in both The m14 ripped apart the brass from long head space blew the mag out of rifle through the shooting bench, the stock split up to my cheek I thought my fingers were gone I couldn’t feel them and was afraid to look if my rifle hadn’t been a military rifle I’m sure I would have been killed all the pressure went down and not back into my face Stick with the… Read more »
I had the very same experience with a Mosin M1A when the round jambed in the chamber when and the bolt slammed home, blowing up the round, cracking the stock and peppering me with mini specs of blood all over my arms, but I didn’t find any cuts on me? Luckily, I sold the busted up rifle at a gun show for a grand!?! THAT was even more amazing???
Who made your M14/M1a? I’m curious as to the manufacturer because it sounds like it may have been improperly head-spaced. This might not have been due to your loads.
Have a m1 caliber .30 springfield armory on back of rifle , the barrel is made by h&r in 7.62 nato sa 11010457 dated 5 65 was told it came the navy, the question is ,is it safe to put factory 7.62 x 51 win. without blowing up, I tried putting shell in front of barrel it looked a little tight not coming to the rifle case , could use your comments, thank you.
@Dubi B, No one is going to answer your question because it could become a legal issue. Perhaps you could take it to a bona fide gunsmith for a physical in person inspection.
@Dubi B, Try using the ammo that is stamped onto the barrel and refrain from ANY experimentation whatsoever.
ALL attorneys for accident, injury, liability lawsuits will tell you the exact very same, AFTER THE FACT OF YOUR, “EXPERIMENTATION” else they would make no money off of your unlicensed, unauthorized, unregulated stupidity.
YOU DO NOT SHOVE A SQUARE PEG INTO A ROUND HOLE!
Mr. Bozeman, I will not do like Mr. Romeu has done and comment on your question like you are foolish in asking it. Instead I will give you the same advice that Wild Bill did. And maybe a little more. First, the rifle you have is probably worth around $2000.00, so I would not experiment. Take it to a gunsmith and have him use a go/no-go guage or a field guage on it to determine headspace. Second, have him check the magazine (clip) area and make sure there is a spacer present. One is required for the M1 when converted… Read more »
Some very good points, but to clarify, please, the spacer block in a Navy 7.62mm Mark 2 (M1) rifle is not required for feeding. It is optional, and only there to prevent someone from loading a clip of .30-06 into the rifle’s magazine. Many of the Navy’s rifles did not even have the spacer block.
The spacer block for the 7.62×51 conversion was sometimes lost when the rifle was disassembled and not replaced. It was designed to allow the shorter cartridge to feed reliably, and was a necessary item for that in an M1. If your rifle feeds without it, that’s good. Most of them wouldn’t feed well without the block to help guide the round, due to the extra length of the receiver. It was also a problem with the prototype M14 due to the first receivers being converted from the longer M1 receiver. And on occasion when the first M1 conversions were fired… Read more »
Mr.Green:
Re Garands converted to 7.62MMNATO or .308 Win., yes there are differences between Military and Commercial rounds on the referenced calibers,as I recall from when I was active in competitive rifler shooting, I had seen a couple of Garands shooting .308Win.and or the NATO round. Re the “block”you mentioned, correct me if I’m wrong, but that would be part of the story, as a new barrel would be required.
Alan, you are correct. The rifle is re-barrelled to 7.62 NATO, and a spacer block is installed. The spacer is there because the magazine (or clip) well is designed for the 30-06 and it acts as a filler and guide to ensure reliable feeding.
You’re rifle is an M1 Grand conversation to 7.62 NATO. This was done to try to save some money and give the Navy a target rifle due to a shortage of available M14 rifles. This is why it’s marked 7.62 on the receiver. If the mag well block is missing a .30 cal clip can be loaded mistakenly. The 7.62 chamber is 1/2 inch shorter. If you run the bolt home the .30 cal round will go into the chamber and stop bolt won’t. This can cause an out of battery detonation destroying the rifle and possibly killing the shorter.… Read more »
The spacer block is only there to prevent a clip loaded with .30 caliber ammunition from being loaded into the receiver. When the bolt runs forward the .5″ round will stop and could cause an out of battery detonation with tragic results to the rifle, the shooter and the shooter next to him. I saw this actually happen once. Fortunately nobody got hurt but the rifle didn’t survive. If you spend enough time on shooting ranges you’ll see it all sooner or later
Mr. Furbush is also correct, in that the block kept the Navy from using clips of 30-06 ammunition in a rifle chambered for 7.62 NATO. It also serves as a guide to keep the shorter round orientated properly for reliable feeding. Both the CMP and Fulton Armory will be glad to sell you one, and it isn’t hard to install. So far, we’ve discussed the difference between .308 Win. and 7.62 NATO, which is in areas such as brass thickness and primer crimps etc., but we haven’t differences in brands of brass, either .308 or 7.62. I think that should… Read more »
Yes it is safe to use. Commercial .308 Winchester in you’re rifle
I have a pair of Indian made Enfield rifles in 7.62 NATO. I have had one round that the head separated from the case while I was shooting them at the range . The gas vented back into my face but fortunately I was wearing my razor fly shooting glasses. I was using Steel cased wolf 308. When this happened. I had already fired several hundred rounds out of the rifles with nonproblems. I no longer shoot anything but 762 Nato surplus through my various 762 bolt actions. I at one point purchase several cases of the steel case wolf… Read more »
Great article and a reminder for myself, since I own a M!A. After reading this article I went to my documentation and it listed my rifle as head spaced to 1.631. I believe this may be due to it being a fully loaded model, just a guess. I only shoot mil spec ammo in it, I had some commercial FMJ ammo where one case failed to eject and I had to remove it with a cleaning rod. I have not tried any major brands of hunting ammo, It may prove more reliable.
Tom McHale, thanks for a well-done, genuinely helpful piece. I recently acquired a Mossberg 800AM in .308 Winchester, Mossberg’s entry into the center-fire weapon field. The weapon, because it was part of an estate ownership and though built in 1970 – 1972, is in 98% condition in both metal and woodwork. I called Mossberg to ask about the proper care and feeding of this beautiful lady. Their weapon specialist, while agreeing that the .308 is loaded more powerfully than the 7.62mm, strongly recommended that I not use the latter round in the weapon. He remarked that while I might get… Read more »
I have an M-1 Garand that was rechambered to 7.72 NATO and given the National Match treatment. It is hard on commercial .308 brass.
Ha Ha , Because I’m a bit of a Dummy RE-Math and an OLD Marine at 81 yrs old and keeping up with the young studs! I’ll have to go with Viper in MT, and shoot what the gun calls for. Hold em and squeeze em gents! if your in the -V- ring I’d say your probably using the correct ammo.
Semper Fi
Machete Eddie
Capt USMC (ret)
Thanks for your service, and HuuuuuRahhhhhhh!
It says what ammo to use right on the firearm. That’s what I run through each of mine except in the case of a firearm which has been certified for more than one (.357/.38Spl, .308/7.62, .22S/.22L/.22LR). For 21+ years. I was provided the correct ammo for my issue firearms and I never had a problem of confusing calibers.
DaveW, MSgt, USAF (Ret.)
Defensor Fortis
HK G3 were 7.62 NATO. One of the improvements PTR did was chamber in .308. I have the PTR 91 and it digests everything just fine. .308 is more accurate though.
I have a Mossberg .308 and out of curiosity I called the company and ask them. The gentleman I spoke with said I could shoot them with no problem. He said the biggest difference was the headspace and the brass. The military 7.62 was a little heaver but had not effect on the weapon. He did say that personally he would not soot the .308 in a weapon designed for military usage and the 7.62 though he had done so and had not had any problems but preferred to used modern weapons with the correct caliber as being the safest… Read more »
If their was a dangerous difference in the calibers then we would hear not stop stories of shooters blowing off their faces with the wrong round whether its 308 or a 223 issue. I can even recall about hearing such a story but only ones involving shotguns or five-seven reloads.
I have two Savage Model 99’s. All I have shot in them is 308 commercial rounds. I have been considering trying some 7.62 X 51 FMJ to see how they perform, but now I may just stay with commercial ammo. I believe both were made in the 1950’s and are gaining value and I do not want to damage them in any way. Additionally, I have a Ruger Scout that says 308, but does not say 7.62 X 51. I guess I’ll contact the Ruger company to see if they have recommendations.
I had the Ruger Gunsite Scout in .308 and I did contact Ruger about shooting 7.62 NATO through it and the reply that I got was that you can absolutely shoot 7.62 through it.
I had a Savage 99 in .308 and no way the bolt would close on 7.62. I also have a Savage Hog Hunter in .308 and it seems to have a bit more generous chambering as I have been able to easily close the bolt on SOME military rounds. But the real question should be “Why in the world would you want to try this??”. A Savage 99 is never going to be used for long distance shots and should never be considered as a plinker that you are going to take to the range and blast away on cheap… Read more »
fishunter.
i own 4 savage model 99’s.
one in 250 savage, two in 300 savage, and the last one in caliber 308 winchester.
in that one i’d NEVER SHOOT 7.62×51 IN IT.
my advice to all here is STICK to the caliber your firearm was designed to shoot.
Some days I’m just not smart enough to shoot a gun. That will be the day I have a 7.62 or 308. Whew. Seems to me the only safe thing is to fire what the barrel stamp indicates.
Ahhh! Trying to impose common sense and logic into the world of firearms? Are you sure that’s a safe thing to do on an online forum full of people that refuse to use common sense and logic?
Would this discussion be the same if we were talking about commercial 30-06 vs. the military round?