Re: I need a little help.
Sounds like you introduced one or up to three variables which altered your results.
Cases: nickel plated brass has different elasticity than naked brass. Wall thickness varies with different manufacturers which changes internal capacity. The same amount of powder in smaller internal space will raise pressure and velocity.
Finally, though I doubt it, the balance could be weighing differently than the elec scale.
Now that have zeroed in on the problem deal with it after the hunt. I'd grab that factory ammo, sight in and go hunt an elk!