Got testing done today. Started a new thread here for the test.
https://thefiringline.com/forums/showthread.php?t=613738
https://thefiringline.com/forums/showthread.php?t=613738
Ruger LCR chambered 38spl P+ (no +P loads used) with a 1.87in barrel.
Mixed 38spl brass
CCI #500 Small Pistol Primers
Brazos 158g SWC (hi-tek coated lead)
5 shot groups unless otherwise noted
HP-38 (aka W-231)
3.1, avg 524fps, SD 22.6, ES 53
3.7, avg 652fps, SD 27.63, ES 75
4.4, Avg 739fps, SD 4.39, ES 11
Notes,
HP-38, Has minimal muzzle flash, small orange fire ball, maybe 1in by 1in. recoil was moderate, not painful.