Way back when Alan Lever had Swedish mausers stacked like cordwood on the floor of his shop, I had an AG42b and very limited funds.
The AG42 is a fun semiauto, long, accurate and light recoiling; but, my goodness, does it fling the brass! The only boxer primed brass that could be found was factory loaded Norma hunting ammo (expensive!!).
So I experimented with making .30-'06, .270, 7x57 and 8x57 into 6.5x55.
It taught me a lot about annealing, reaming and patience. They all worked well, and survived repeated loadings until they were lost in tall grass or snow.
It will work; but it's a lot of work.
One afternoon I was making .308s into .243s and I got the bright idea of running a .308 into the 6.5x55 die. It looks a little funny with the short neck; but it worked great in the AG42, no trimming or reaming. Maybe in a good rifle you might worry about the erosion on the mouth of the chamber; but I figured that I'd perminantly converted so I didn't worry.