Not surprising results from many factory barrels,and manual data.You may have completely different throating and barrel from what Nosler used to work up their data.
Seen it many times. Different barrels can have a substantial effect on velocities with the same loads.
Spot on, each bbl/chamber is an individual.
Loader the mostly may as well be wildcats.
Very true. Some fellas would croak when working up wildcat loads. Tis no different....