Factory Hornady V-Max 55gr measures right at 3550 with good extreme spread and SD (33 and 16). I cannot seem to get 4895 or 3031 to come close to the ES or SD. I'd like to get these Sierra 55gr Spirepoint BT at about the same velocity. I'm getting near the same velocity but the ES and SD is no where near. Is there a better powder? Tried 4064 and AA2520 they are much worse. I also seem to be getting some split necks even with this lower velocity.

Any hints?