Bryan -
I see your data corroborates cllaborates confirms the belief that Trail Boss is not only "faster burning" than Unique, but also
the pressure curve has a sharper initial slope ...
I am intrigued by these findings of yours:
"Replicated vintage black powder loads used pre-1884 unheadstamped cases that have the largest inside balloon pockets available. They created the highest pressures and fastest velocities, as advertised during that timeframe. I believe this to be due to the amount of powder that is down beside and "beneath" the initial ignition of the powder...possibly creating a "boost". The more shallow the pocket, the less "boost" created.
WRA era headstamped cases have a more shallow balloon pocket and produced medium pressures and medium velocities, consistent with advertised ballistics of that timeframe.
Modern cases, such as Starline, have no balloon pocket and created the least pressures and slowest velocities. "
This implies a far more complicated burn-and-pressure model than most of us thought, dependant upon container and charge shape.
There have been many studies by the military regarding artillary artilla different shaped "holes" extending through
the length of the powder charge in artillary artillacannon shells ..
thanks very much, I do hope soemone with more expertise in this will chime in.
yhs
prof marvel