"As I remember, .38x55 brass is longer than .375, .32 Win.Spl, .30-30.
So, if you are trying to use .38x55 in a lever action, and you have .375 Win dies, it would have to be trimmed to be able to crimp in the bullet's crimping groove. "
.38-55 is longer than .375.
So are blown out .30-30 and .32 Special.
ALL have to be trimmed to proper length.
But that doesn't negate the fact that the .38-55 case isn't as strong through the head and lower case walls as any of the other rounds, so if .38-55 is repurposes to .375, loads need to be kept on the milder side.