Caliber & twist rates
caliber twist rates number of grooves
22 CF 6.5 7 7.5 8 8.5 9 10 12 14 6
.224
.243 7.5 8 8.5 9 10 11 12 13.5 14 15 4 and 6
6mm
25 cal 1-8 through 1-14 4 and 6
.257
.264 8 8.5 9 9.5 10 11 12 4 and 6
6.5mm
270 cal 7 through 1-12 4 and 6
.277
.284 8 8.5 9 9.5 10 11 4 and 6
7mm
30 cal 8 9 10 10.33 11 12 14 17 18 4 and 6
.308
.338 9 9.5 10 10.33 11 12 6
35 cal 1-12 through 1-16 6
.358
Any twist listed is possible for any of the calibers if you require
something not listed we can most likely do it