The 129 LRAB went into 3/4" with retumbo but only at 3075 fps. Gotta try a faster powder.
Faster? I think slower would do you well. Upon the advice of member RCamuglia (not sure on the spelling) I picked up some WC-872 from wideners.com
They had 8 lbs to me in 2-3 days. Should really show us some speeds.