Cast vs jacketed pressure?
This has probably been answered somewhere, but I can’t seem to find it anywhere. How is cast bullet pressure related to comparable size/weight jacketed bullets? Checking my manuals, it seems to be a hodgepodge of sometimes seemingly contradictory data. Sometimes when the same amount of powder is used in cast and jacketed loads, the cast bullet is faster with less pressure. Sometimes cast is faster with more pressure, sometimes slower with more pressure, and sometimes they are about the same. What gives here? I’m talking same caliber, same manual, same powder; not across multiple manuals.
I always thought that cast bullets had less friction, and would produce higher velocities with less pressure than jacketed, but I guess not always.
Pressure- Cast vs Jacketed Winchester Data 1996
The Basis for Compositional Bullet Lead Comparisons
Bullet leads analyzed from CCI, Federal, Remington, and Winchester have contained up to 0.42 percent arsenic, 6.8 percent antimony, 2.5 percent tin, 0.2 percent bismuth, 0.22 percent copper, 0.031 percent silver, and 0.011 percent cadmium. The wide ranges in concentrations of all of these elements within sources provide for thousands of distinguishable melts of bullet lead at any one time.
Lead vs Jacketed. Pressure & Velocity (more) Hodgdon Data. 2020.