I’m loading 75gr Speer Varminter bullets behind 41.5gr of H4895 for my 18” barreled AR10. The chrony averages 3345. Is that decent for a 75gr bullet or can I bump it up to 42gr safely in a (full) ? semi auto?
With that twist and that bullet weight I’d say if it’s shooting good now I’d be done with it. Little faster twist barrel you may get it to stabilize faster but I’d imagine you’ll start seeing a lot of flyers really pushing it harder.