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.
I said:
"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.
F. Guffey