H4350 is great powder and I use it my 260 Rem (40.7gr). While the 6.5 Creedmore has a ever-so-slightly smaller capacity, I'd definitely give it a shot,... literally

You should also try Reloader 15 & 17 to see if they'll do the job. The Berger 140gr VLD's, Lapua 139gr Scenars, and SMK 142's all shoot lights-out in my rifle.