From Pac-nor's web site:
Caliber and Twist Rate Chart
Highlighted numbers are standard or popular twist rates.
25 (.257")
3 groove 10" 12" 14"
4 groove 11"
5 groove 9" 10" 12"
6 groove 8" 14"
Polygonal 10"
I have 1:9 barrels on a .250AI and a .25/06. Very happy with the results.
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing."
Robert E. Howard
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