View Full Version : Argentine 7.62 vs Nato 7.62
October 7, 2009, 11:15 PM
Would someone tell me the difference between the Nato 7.62 round and the Argentine 7.62 version? On a milsurp rifle, how do you tell the correct chambering. I picked up a Modelo 1909 Mauser and was told it was chambered for the Nato round.
I just started a few years ago and it would be nice if it were in fact the Nato or 308 round and easier to buy I guess.
October 8, 2009, 12:01 AM
I have no experience with either, but don't shoot it until you are 100% sure of the proper caliber.
October 8, 2009, 05:54 AM
7.62 NATO/308W is not an Argentine 7.65 B/M (Argentine), I will not say 'not a problem' the 7.65 Argentine (Belgium Mauser) is too long from the head of the case to the shoulder to chamber in the shorter 7.62 NATO/308W chamber. Your rifle should have 7.62 stamped (or ground) into the receiver that identifies it as a 7.62 Conversion. As to the difference between the 308 W and 7.62 NATO? After I size and or form the cases the cases fit my dies and chamber, there were rifles that were converted from 7x57 barrels, the barrel was bored and because of the longer chamber were inserted with a bushing.
and the 308W/7.62 NATO is too large in diameter at the shoulder to chamber in a 30/06 chamber, I could say that is not a problem but that would not be true, there are some large 30/06 chambers and a few very shooters that are very determined when chambering a round.
October 8, 2009, 06:14 AM
The Argentine 1909 Mausers were originally chambered in "7.65x53 Argentine", also known as "7.65x53 Belgian."
A 7.62 NATO / .308 Winchester cartridge will fit in the Argentine magazine, chamber, and fire. However, it will have excessive headspace and is rated to a considerably higher pressure than the Argentine cartridge.
Some rifles were converted to the NATO cartridge later in their lives. This was done by setting the barrel back and rechambering. Sometimes the barrels were not marked to indicate the new chambering. You can check by removing the bolt and dropping a cartridge into the chamber. Doesn't matter if you have a 7.65 or 7.62 - the difference from the shoulder to the base is almost an eighth of an inch and it will be easy to tell if it's the proper cartridge.
October 8, 2009, 07:44 AM
"chamber, and fire" 7.65 BM, .434 at the shoulder: 30/06, .443 at the shoulder: 308Winchester/7.62 NATO, .455 at the shoulder: The 308W/7.62 NATO is .011 thousands lager in diameter at the shoulder than the 30/06 case at the same point when measured from the head of the case, meaning when the 308W is chambered in the 30/06 the shoulder must be sized down when the bolt closes, for most when the resistance is felt they determine there is something wrong.
The 7.65X53 BM case is shorter from the head of the case to the shoulder than the 30/06 (.443) and is smaller in diameter at the shoulder (.434) by .021 thousands, this would lead me to believe there are some very large 7.65 chambers out there or some are more determined when chambering a round than I thought.
"Some rifles were converted to the NATO cartridge later in their lives. This was done by setting the barrel back and rechambering" Setting the barrel back for the the shorter chamber (308W/7.62 NATO) would require a .216 set back at least, this would just about remove the seating ring at the end of the threads, and even if this was done the bullets would be a little loose unless they designated the new chamber 7.65/08, then there would be a concern one of the 7.65/08 cartridges got in to a Spanish 7.65 Conversion.
Except for the 7x57 conversions 7.62NATO conversions got a new barrel, when the Turks converted the 7.65X53 to 8X57 they replaced the barrel and notched the receiver.
October 8, 2009, 07:55 AM
"A 7.62 NATO / .308 Winchester cartridge will fit in the Argentine magazine, chamber, and fire. However, it will have excessive headspace "
As I said if some go-rillo chambers a 308W/7.62 Nato in a 7.65 BM chamber and manages to fire it, when fired there will not be a head space issue because the 308W will be wedged in the chamber, the wedging will be caused by the sizing of the case as it is chambered, there will not be a pressure issue because of the loose fit between the bullet and amd bore, if someone manages to chamber and fire the 308W in the 7.65 chamber they will have accomplished one thing, for all the effort they will get a fire formed 7.65x53 with a very short neck.
October 8, 2009, 11:24 AM
Many thanks to F. Guffey and TRX for the much appreciated information. I had purchased this three years ago from a milsurp dealer with whom we share a close friend. I have not fired the rifle, nor had the time to do anything except checking with a 7.62X51 go/no go. The go chambered and the no go didn't.
I will remove the stock and bolt and do as you suggest...checking for markings and how the 7.62X51 fits.
Thanks you both again for your help.
October 8, 2009, 09:02 PM
I have not encountered any Argentine 7.65 rifles that have been modified to use 7.62x51 (7.62 NATO), but some Chilean 7x57 rifles were modified to that caliber by reboring and re-rifling plus the use of a chamber sleeve inserted into the drilled out end of the barrel. The original barrel and its markings were preserved, but there are questions about the conversion method and what, if any, problems might arise from its use.
A very common conversion of the Argentine Model 1909 is to .30-'06; the magazine has to be modified, but the chamber will cleanup quite nicely. Accuracy will be mediocre, but acceptable to some buyers. The difference in cartridge base size, often a subject of dire warnings, is insignificant and in fact, specs overlap.
October 14, 2009, 08:16 AM
I do not see a lot of misinformation, from the beginning, the 7.62 Argentine does not exist, if the barrel is set back and chambered to 308 W/7.62 NATO the rifle would be called the 7.65/08, the 7.65 BM was chambered to 30/06, with a little problem at the neck unless the neck was reamed to 7.65, then the chamber would be called 7.65/06.
I believe there was a little confusion when bimmer*tr posted 7.62 my mistake when he was thinking 7.65 Argentine.
"As I said if some go-rillo chambers a 308W/7.62 NATO in a 7.65 BM chamber and manages to fire it, when fired there will not be a head space issue because the 308W will be wedged in the chamber, the wedging will be caused by the sizing of the case as it is chambered, there will not be a pressure issue because of the loose fit between the bullet and and bore, if someone manages to chamber and fire the 308W in the 7.65 chamber they will have accomplished one thing, for all the effort they will get a fire formed 7.65x53 with a very short neck"
Notice the part that covers the difficulty in chambering a 308 W in a 7.65X53 chamber then notice the part where bimmer*tr says he chambered the 308 W go-gage in the chamber and the part where the no-go gage would not chamber.
"Many thanks to F. Guffey and TRX for the much appreciated information. I had purchased this three years ago from a milsurp dealer with whom we share a close friend. I have not fired the rifle, nor had the time to do anything except checking with a 7.62X51 go/no go. The go chambered and the no go didn't"
Then put the two together, chambering a 308 W in the 7.65X53 will size the case down with noticeable effort because the case will size down and get longer, chambering the go-gage will or should be imposable, the go-gage chambered, the no-gage did not, it is not an Ackley or magnum chamber, the chamber length is between a 308 W go-gage and a 308 W no-go gage.
Then read through the responses and find the part where chambering a 308 W/7.62 NATO can be done if the 30/06 chamber is too large in diameter, or the person chambering the round is very determined because the 308 W is larger in diameter than the 30/06 by .011 thousands at the shoulder when measured from the head of the case to the same point of the body, then find the part where TXR says it can be fired in the 7.65 chamber. will have head space issues and raise pressure, it is said chambering will be difficult, head space will not be an issue and pressure will be lower because of the difference in bullet diameter and bore/land diameter.
Dick Culver, author, while shooting at Perry mistakenly fired 7.62 NATO on his M1, accuracy did not suffer (much), he did not notice the mistake until he picked up his brass, the M1 does it's own chambering, if he had been shooting a bolt type rifle he would have noticed the resistance to chambering OR the chamber in his rifle rifle was too large in diameter.
Once I advised someone to chamber a 308 W/7.62 NATO rifle with an Ackley Improved 30/06 or a 30 Gibbs, he thought I had given the ideal too much thought, he chambered his rifle to 30/06, thin discovered the 30/06 reamer will not clean up a 308 W/7.62 chamber, seems the shoulder of the 308 W is too large in diameter and when test fired the cases removed from the chamber show evidence of a ring JUST AABOUT WHERE THE SHOULDER OF THE 308 W REMAINS. Those that left the ring claim it is a good way to measure the SKID MARK? when cases stretch and or flow if that is what happens?
Chambering a round in the M1 can size a case, chamber a 308 W round in an M1, do not fire it, remove the chambered round and measure the the diameter of the shoulder, if a 308 W chambers in a 30/06 chamber, the body chamber is at least .011 larger in diameter than it needs to be.
October 14, 2009, 08:24 AM
and the M1 chamber is larger in diameter for ease of chambering the same ammo used in the M1917 and O3 Springfield by about .0003.
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