pat I have never worked with a 7 Weatherby,and know the manuals show it similar to the Mashburn;but i also know it has about the same capcity as the Remington case,so I really can't explain how the weatherby gets where it does,except due to the freebore,a 26" tube,and Weatherby-type pressures.
I have had a few "long throat" 7 RM's and they nudge right into 7 Weatherby load data territory.But again, I always felt I was leaning a bit hard.The thing that struck me about the Mashburn was how "easily" it reached these velocities.And velocitiy variations are very low,maybe 10 fps in a 5 shot string,at least with H1000.I think Art Mashburn did his homework.
