If you are competing with it then you want the barrel length. Barrel length = bullet velocity, higher bullet velocity = more fudge factor on wind calls. I just shot one of the harder matches out there with a 26" barrel and a can, no issues with length. I am able to attach a sling to a spot near the rear of the bolt (krg w3c gen 4) so it doesn't hit the dirt, if you are a shorter guy this may be a problem.
If you are just shooting paper or rarely shoot past 500yds then it's irrelevant.
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