quick question...............Have a 45-70 barrel (34") with a 18 twist. Been shooting 520-525. I want to try the 405 gr. (WHY????? just want to) Was told the 18 twist is not for light boolits and to use the larger ones. Just for silhouette and paper out to 200 yards...............When I look it up, all are talking about the 405 boolits. If so, would I keep the 70 of black gold????????Thanks beng