The 7mm 180 grain HPBT MatchKing was created in response to requests from top-level F-Class shooters. Sierra has designed these MatchKing to provide a higher weight/higher B.C. alternative in our 7mm line. This bullet's 12 caliber secant ogive and lengthened boat tail make it the perfect choice for the discerning 7mm long range shooter. Please Note!! This bullet requires at least a 1x8" twist barrel. my rifle on order has a 1-9 twist brux has anybody tried these in a 1-9?