There are some really usefull nitro powder equivalents for cordite formulae around, however does any member have similar formula for IMR 4198. They are good for providing approximate loads for old Brit ctgs. As always start at least 10% below and work up.

Other formulae that I am aware of are as follows.
1.10x IMR 3031 = cordite
1.19x RL15 = cordite
1.31x IMR 4831 = cordite
40-44% IMR 4198 = black powder

Based on the relative burning rates I would imagine that 4198 is close to 1.
Does anyone have better data than this guess?
Fraser

(Added a comment regarding a warning re using IMR3031)