I have experimented with shot cartridges over the years. I have made them from longer cases and tried various set ups.
However, after all was done, the best results in all calibers that they were offered was to use the Speer (CCI) Shot Capsules. They are BY FAR the best way to go.
The most important thing I discovered is that the smaller the shot the better results I got. Revolver shot cartridges are NOT good small game loads. They are only satisfactory at 20 FEET or so, maximum (plenty enough to shred a snake that is close enough to hurt you - if he is farther away, he can't hurt you). #12 shot does MUCH better than anything larger.
You can get #12 from Ballistic Products:
http://www.ballisticproducts.com/prodin ... mber=02612
#12 is expensive ($29.95 for ten pounds + shipping). The good part is it doesn't take much per load and ten pounds is pretty much a life time supply for you and a buddy.
#9 shot is available locally and is considerably less expensive but also less effective.
What you want is a TIGHT pattern. Energy per pellet is not an issue at those close ranges (3-20 feet) and #12 is just flat better performing.
I have loads for .38/.357, .44 Special/Magnum, and .45 Colt. I have often backpacked in rocky country and shot is MUCH safer than bulleted loads on rocky ground. Actually, a good action shooter has little problem being VERY effective with a bulleted load but it can be quite dangerous of a ricochet at close ranges.
FWIW
Dale53