help with length and twist rate for a custom creedmoor barrel

[mpncc]

I tore apart one of my dpms format 308's and plan to put in a 6.5 creedmoor barrel. I have read around and it seems most recommendations were for 24-26" and twist rates 1:8 or 1:9.
I would like to shoot from 120gr to 140gr (I know all the way through but applications from coyote hunting to LR shooting) and I do want to be able to take it in the field and hunt from a bipod with it so I was thinking maybe 20-22" but obviously don't want to lose to much ballistics to shoot LR. I will be researching but would like some input from some creedmoor shooters.
thanks in advance for any input

 

[ss355]

My understanding is that some of the longer 140s require a 1:8 twist to stabilize. My DPMS is a 1:8.5 and it handles the Hornady 140s just fine, but I haven't tried any other 140s yet.

If you plan to schlep the gun around in the field for hunting, I'd say go 20". Yeah, you'll lose a few FPS compared to a 26", but for typical hunting distances that won't matter and for extended range target shooting you just dial a tad more elevation.