It ain't rocket science. Take 158 gr. bullet. Drill hole, weigh bullet. Lyman has weights for 150 or close to whatever weight the bullet ends up to be. Try to match you bullet close to one of those with a similar profile. Start out conservatively like any new load.

If there is any difference in data between a 158 FJM or 158 JHP it's minute, if there at all. I don't think there really any other significant variables. Changes in c.o.g. or B.C. or SD aren't going to make any difference in internal ballistics. The bullet is wedged in the barrel and isn't going anywhere except out the end. They may not be accurate, or fall to the ground at 20 feet, but that's not dangerous. For close range stuff I don't think you'd notice much.

I'm going out to my garage tonight and drill out a few for the heck of it and probably shoot them at the range Wednesday. I have some swaged soft bullets and some hard cast. I'll figure out some way to capture these and take a look at them. Box full of stuffing?

The only question i have is how soft should the bullet be. Again, casters sell these. Maybe get a clue from them.

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