yes im using the 375 data as my barrel is bored to 375, and yes on the brass but this is with winchester brass, winchester cuts their 38-55 and 375 brass to 375 cut length. guess its a liability thing. but any way look at the loads for 38-55, in a modern rifle with 250 gr bullets you can stop just about anything. you can go up tp 300+ grain bullets in lead!!!
the load out of mine with the 200 gr sierras is so accurate and my brass is showing no signs of pressure. look at buffalo arms loads for the 38-55 and the 375 youll be surprised.
im glad i went with the 38-55. oh in case you didn't know, the 30-30 win is simply a 38-55 win necked down.
SB