Note that when loading by the equal volume method a 1oz shot measure will hold about 2½ drams of BP. Both will vary a little according to shot size & hardness or powder granulation, charcoal used & "Moon Phase" on the day it was loaded etc, etc, but none of this is generally significant. As PeteM said this is a very good starting point for 12ga. In 12ga I prefer 3FG powder for i or 1 1/8oz loads but generally switch to 2FG if going to 1¼ oz. According to an old Rifleman industry standard for BP volume is .115 CuIn per Dram & volume for 1oz shot seems to be about .288 CuIn. Shot volume calculated from Hercules/Alliant Reloaders Guide.
