Anyone know how much would be lost of the shank end of a 700 bbl going from a std 280 to 7x57?

Asking for a friend here.

7.5 millimeters.

Looks like a minimum of 0.35 (inches), but I am no gunsmith!

I don’t have the case dimensions handy but the shoulder diameter is going to be the critical dimension. Enough length has to come off to let the 7x57 reamer clean the shoulder area of the 280 chamber. Probably more than the difference in overall case length.

I would guess about 3/4 inch beyond the difference in case length. GD

I did it the other way (sorry).
A good deal for 1903 Remington sporterized in 7x57 was OK but i thought a 280 would be better it was !