As Ronemus stated 75 gr hpbt is one of the highest BC s you ll get to run through magazine. That said I ve been able to get 75 eldm to stabilize out of my 9 twist Vanguard with a stout load of H4895 and 3000’ elevation. Shot so well at 650 that a machinist friend build me a spacer for my Mag and by removing short factory spacer and putting in our shorter machined spacer I can run those 2.460 oal 75 gr Eldms through the magazine now. It makes my 223 perform much better at distances beyond 350-400 yards.