It's hard to really pin point anything when you don't know the persons shooting or reloading ability (not saying you are bad at either).... But having another person also shoot it can eliminate a lot.

What makes you think the 1/12 twist is a problem? It's not the twist that I'd get but tons of small groups are shot with that twist all the time. Trying some premium 168 factory ammo would be a good start- and then in the reloading I'd try some more jump- .030 really isn't much jump. All of the bullets that you mention are bullets that don't need to be in the lands.