38-55 cast boolits using 2400 powder..247 grain boolit. what is the variances

[Throckmorton]

I have written on a slip of paper that I can use as little as 12 grains,but no idea where I got that info.
Does someone have data for using 2400 ? I'd like to stay at the low end for my old winchesters,but I'd like to know that it is good solid data.

thanks !

[hydraulic]

I'm using 16 grs. of 2400 with a 250 gr. plain base bullet that works well on 100 yd. pigs.