Gentlemen - thanks for the information & smokeless loading data...
I've been working the bullet with the Powley Calculator and with a SF - Stability Factor greater than 1.5, a bullet is at maximum stability.
From 1247 up to 1523 fps, Powley Cx says the 375292 is maximally stabilized and the minimum twist is 1:18.
Powley Minimum Twist Rate Calculation **
SF 3.35
V 1247
BL 1.18
WT 323
DIA 0.381 TWIST = 18.0
I would be very comfortable with the results loading it with 42-46gr of FFg but with smokeless I'm clueless.
I had CPA ream the chamber for breech on the Uberti HiWall to have a companion bullet for the Douglas 32-40 barrel on the CPA. The Hudson 375293 is an accurate breech bullet for the 32-40 - now I just have to get better groups out to 300yds with it. J Louis ... I'm working on it!
I've got both 4759 and 4227, so I'll try both powders. When Hodgdon discontinued 4759 - I bought 6 lbs so I'm good for a goodly time
Note: Even with a 44 1/2, the 375292 cannot be breech loaded with a plugged case because the bullet is too long - 1.18". That's why I'm looking for another breech seater vendor