I am working up some loads for my marlin 45 colt, and I have some CB I got from a forum member and I can't find any load data in my books for boolits that weigh 289-291 gr? The powders I have available are
Hercules 2400
Win 231
Bullseye
IMR 3031
IMR 4831
IMR 4350
BLC-2
Varget
How do you go off the reservation so to speak and work up a starting load?