I think savage had these at 1:9 or 1:12. You could mark a rod with tight fitted patch and measure the twist if unsure.
The 221 Fireball IMHO is best suited at 1:14 Although at 1:12 it would likely perform ok.
What kind of bullet weights are you wanting to run is probably the bigger question.
I'm a fan of the .221 FB. I think it is highly under-rated!
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