I'm having a 24" Varminter barrel made, I intend to shoot 140 grain Sierra MatchKings at near 3200fps. I live in a colder climate and will be shooting at altitudes of 3000 to 10,000' . The barrel twist calculator i used said a 1:9 twist rate is best. What would you suggest?
the 1-9 would probably work fine bt the 1-8 would certainly work and if you ever wanted to shoot heavier bullets it woulden't be any trouble. The slight differance in twist isn't going to make any negitive effects some folks claim that it will reduce velocity , I have yet to see this proven to any significant degree.
I don't think that you'll be shooting these bullets fast enough to blow them up from over spinning and I don't think that you will have any trouble with "overstabilization" another claim I've yet to witness.
Mine is a 1:7.75 27 inch gain twist barrel.Very accurate at 2900-3000 fps.When you get it up to 3200 with 140's please post your loads.I haven't found a powder or load yet to get up to that velocity.I have tried Retumbo,H1000,Imr 7828ssc and am about to try Varget when the weather warms up.