Someone called and said they have a problem with a 280 Remington, seems it has a ring around the neck after firing, they claimed sizing corrected the problem. seems the natural thing to do with a 7mm57 was to ream the chamber to 280 Remington, the problem most 7mm57 have larger chamber necks and when reamed to 280 some of the chamber is not removed. A fix would have been to throat the chamber and clean up the chamber with a neck chamber reamer.
30/06 Argentine, there was the 30/06 reamer, the neck diameter of the 7.65 is .017 larger in diameter, the shoulder 'from the head of the case to it's shoulder is .188 shorter than the 30/06 when measured from the head of the case to it's shoulder and the Argentine case length is .384 shorter than the 30/06 meaning most if not all of the 7.65X53 chamber is removed. If the reamer used to cut the chamber was a 7.65/06 the neck of the chamber will be the correct size and if the reamer cut the throat 7.65 (.311) bullet should/could be used.
If 30/06 reamer was used a .311 bullet could cause the neck to be too tight and the bullet would be required to sized down when it hit the throat (cone).
With measurements most are + or - a little.
In the perfect world the correct reamer would have been used and for sizing cases a 30/06 full length sizer could have been used with a 7.65 (.311) sizer ball.
F. Guffey