My 38-55 is a 336 Marlin 30-30 bored out by JES. He uses a .3755-.376 groove size so it's really a hybrid .375 win/38-55.
I've pretty much settled on 3 loads, all from an Accurate 38-250B mold I ordered plain based.
10 gr Universal for a general target and plinking load, about 1235fps in this 20" carbine. This one is light enough that my slight built 5th grader Grandson handles it easily.
21 gr 4198 with a tuft of dacron for deer hunting in close quarters. Gives about 1400fps, penetration is NO problem.
32gr 3031 PC bullet. about 1600 fps. For when I feel like "Git er done!!" Noticable increase in recoil and muzzle jump.
All are very accurate, I think I've posted a picture before of the plinking load at 50 yards having 3 shots in a single, 3 lobed hole.