I was thinking of finding a 99 that's had a rough life and giving it a new life by having it rebored to a 6.5. any thought, would it work with rotary mag or just a magazine, any recommendations for a Smith to do this.

You ain't gonna rebore a 250 to 6.5, so the only other option is a 22HP, and that's a whole other can of worms.

Just a thunk.

Of course a 243 or 22/250 would work.

don't rebore, just rebarrel and you get a decent shooter

I have a 99F in 260 that was a 243 before being rebored. It is quite a good shooter and deer slayer.

A 99C in 6.5 Creedmoor would be a cinch, but I don't know how well the 6.5 Creedmoor would work in the rotary magazine 99s.

EDIT: I had a tang safety Ruger 77 RSI in 243 that wasn't an accurate rifle, so I had it rebored to .264" as a 260 and it became a much more useful rifle.

It has been my experience that Savage 99s are typically more expensive to rebarrel because there are few 'smiths who have much experience working with them and the design requires a bit more machine work and hand fitting than bolt actions that are more frequently used as donor actions.