There is a difference between 38/40 dies such as RCBS. They make two 2 die sets. One for rifle, jacked bullets only;
the other set is for lead bullets, a different size bullet. The lead bullet should be .401 BH 15-17.
I shoot on average 11 to 13 thousand lead bullets a year just in that caliber, CAS.
The hand guns I use have different size cylinders, Ruger Vaquero, Colt SAA, BOTH DIFFERENT, dies must be adjusted for
both, my rifles I use are Winchester 1892, original, only use once in a while, Uberti 1873, Lightining rifle pump different,
Miroko Brownings 2 different rifles, all used in competition, each had to be adjusted to resize fit all.
If you have the right die set there is still a problem if you are using a progressive. I use a dedicated Dillon 650 to make 38/40 ammo, I use 2 two toolheads, one to decap and resize only, I have about 3400 in use at one time, meaning, I resize,decap
all at one time, put in tumbler, then a large box ready to load all 3400 as needed. The second tool head has the other dies.
Watch the shell plate if you do all functions together the shell plate presses down against base of machine stopping it from resizing the entire case. Stop listening to music pay attention to reloading. good luck, Lee
The Ruger vaquero in 38/40, all of them had a cylinder problem, the end of the cylinder was too small, it had to be
reamed a tad. I have 5 vaqueros in 38/40, 4 nickel Colts SAA in 38/40