I had a Buddie cast me some 38-55 in .380 diameter and would like to load it with some IMR 3031:

The cast BHN runs around 13 and would like to keep smokeless loads around 1400 fps ;

The bullet cast in 264 grain plain base any ideas on how much powder to start to use I was thinking more like 28 grains to start?

I believe that 28-grain charge will give too much pressure & velocity for those soft plain-base bullets. Look up a load in the Lyman handbook for cast 38/55 loads.

26 grs of IMR3031 will give you a little over 1400 fps and 32 will give you over 1700 fps.

thank you: I start with 28 grains and see how the barrel leading goes since the BHN is only 13
The bullet is soft should make a excellent deer load with FPS around 14 to 1500 fps max: