Since obtaining the first PacNor (button-rifled) 1:18" twist five-groove barrels, in spring, 1997, all but one of my .30 Cal. barrels (for both Hunter Rifle and VfS) have been 1:18" twist: @ sea-level/STD conditions, this twist, in combination with FB bullets, up to 1.050" long, will impart
>Sg1.4
*.
There is no penalty for the
HUMONGOUS Sg safety-net provided by the [popular] 1:17" twist: for bullets based upon the
1.00" jacket length, Sg1.7; on the
.925" length, Sg1.9 - exit muzzel, followed by
ONE precession cycle and, "imitating Rip VanWinkle" . . . just one of the, "dirty little secrets" . . . Oh, which also applies to the 18" twist - again @
>Sg1.4 . . .
The only 1:17" twist barrel I've used was a [typically excellent] Kostyshyn (button rifled)- I went 17" because that's all Craig offered. All of my PacNor five-groove 1:18" have proven their worth, as have the 4 & 5-groove Bartlein barrels, and a pair of Morrison 1:18", which are cut-rifled.
A good barrel is just that - a good barrel, regardless of cut vs buttoned vs land/groove count.

RG
*Shorter bullet = higher Sg.