AK - you ever shoot .32 shorts out of a .327 mag?
How bout .32 longs in a .32 H&R mag?
How bout any of the above in a the .32 H&R, or .32 Long in the .327 mag?
OK OK.. I know, not the same...
My barrel is marked .308 win, can I fire 7.62 nato?
How bout a .380 firing 9mm kurtz ammo? (this is an issue of symantecs)
.38 sp in a .357?
.223 in a 5.56 nato
.30-30 in an .30-30 AI?
Honestly, I could probably fire a .307 win in a .308 win.. .but I don't see the reason to try (both a .308, case dimension are just about identical, and the .307 is a lower pressure round that will chamber and headspace correctly off the .308 chamber but you'd have to have a very generous bolt face to accomdate the rim).
What is marked on the barrel isn't always the definitive list on what a firearm will shoot.