Have a 1952 722 222, 26" perfect bore. 22 Nosler is fatter, longer same head size.

Feeding could be issue--- follower change ? Plan to use light bullets.

Nosler claims 55 gr @ 3500 fps w/24" bbl., 3550 with their 55gr 22-250 24" bbl.

Would 22 Nosler reamer clean up all 222 chamber ?

Don't take this wrong but what's the point....the cost of the work would buy you a good swift....and I you wouldn't loose your wonderful Duce...

I think that the 22 Nosler is essentially a rebated rim SPC case. So you will probably need the follower from a 6.8 SPC m700 to ensure feeding, if it won't do it off the bat.

I wouldn't go through the trouble except maybe in an AR. The .223 AI gets close enough with cheaper brass. Have heard a lot of sob stories with the early versions splitting cases and not achieving velocity too.