I go through something similar to this every time I go to work up a round ball load in a bore gun....20 bore, 12 bore and now 16 bore. Confirm my reasoning here:
A normal 16 bore load is 1 to 1 1/18 oz. of shot...right? That's what I've been loading in my pre-WW1 Ithaca 16 bore double for years. Ok, the .678 mold I got from RCBS throws a round ball of 470 grs. By my calculaitons that's 21 grains lighter than a 1 1/8 oz load of shot. Therefore there should be no reason my old Cape gun will not digest the round ball with 3-4 drams of Ffg, correct? Obviously I would start at 3 drams and work up, if needed. Thoughts, opinions, advice?