This is a fun topic that I got into 10 or 12 years ago pretty deep. I actually bought a box of 12 ga loaded with #9 because that's actually a lot of shot when you break them down and it was cheaper than buying a whole bag of shot I'd never use up.
That aside, I worked on 38s with the capsules, that was fairly easy and I did pattern a few out of a 2" sp101 and maybe the BH but I can't remember. I got a couple boxes of factory cci for the 1911 45, and thought I could make those too. I started out with 308 brass cut down, sized, then formed a neck with a 40 s&w die, made cardboard powder cards and plastic shot cards, and crimped with a 38 spc seater iirc. They work and function, only shot 1 snake with them, but I did shoot some plastic bottles out of the air lol. Set an empty bottle on top of a water filled bottle, small Gatorade bottles work well for this. Shoot the bottom one with a hp then the top one with the shot shell as it flies through the air. Amaze your friends lol.
After loading those 45 like that, I kind of decided there's a good reason the factory ones are so expensive. They're a pita to make.
