TX200 1:17",
HW97 1:15.5" ,
Rapid Mk 1 1:14",
Steyr 110ft 1:17" ,
HW100 1:16",
CZ (S200) 1:18.5",
BSA 1:18.5",
Steyr barley twist 1:15.5"
HW50 1:16"
(these are all measured from my own rifles/barrels apart from the Steyr barley twist, you may find that your barrel is different, it seems manufacturers change the barrels/twist rate from time to time)
Officially the LW barrels (which are fitted to a lot of different rifles) are 1:450mm (1:17.71"), this includes the polygonal barrels.
I have been told that slow twist rates (1:20+) would be best for accuracy but I have also been told that a faster twist rate is better in the wind. This is for sub 12ftlbs.