78.5 grains produces 2950 but that’s showing some increase as barrel break in occurs.
The increase also may be due to a buildup of carbon in the throat, which increases pressure and thus velocity.
Learned about that issue with one of five 7 WSM barrels.
The solution was an overnight soak with Hoppe's Benchrest solvent and a brush. The first patch the next morning looked like a glob of mud coming out.
The process was repeated with three nights of overnight soaks and brushing before all of the carbon residue was all cleaned out.
Velocity dropped back to the numbers of the original load work up.
So, just an issue to keep in mind.
