If I am not mistaken the SV's are 1.365 in diameter and like you said 6.5 inches long. They were designed for a LV rifle. That is: a short LV barrel @21 inches. I have seen some longrange rigs with these small actions. HV barrels @28 inches. Larry Isenhour has one and shoots IBS 600 yards and does very well with it. If you already have a SV, I would not hesitate to use it, But if I were ordering one from BAT, I would get a 1.55 diameter round SB model. I have one and love the short throw 6.5 inch bolt, plus you have extra bedding surface and weight to offset the heavy barrel. Just my .02 cents.
Samuel Hall, Boonville,NC.