I used to work for the company that owned the now defunct "BBM". BBM made shotshells in .45 and 9mm. One cool thing about the BBM design was that it would feed and fire in anthying that would fire ball ammo. We even had a Thompson full auto that worked well with it.
All that aside, if you want to shoot shot, you want to consider the following:
- keep the shot awy from the rifling... an improvised rolled paper or plastic tube will keep the shot away from the rifiling.
- if you really want to use shot, remove the rifling from a "shot only" gun altogether. WIth modern handguns, that is a legal no-no. With pre-1898 stye guns that is acceptable.
-consider putting some sort of "short slug" on top of the shot column to put something solid in the center of the pattern. If you have access to a Corbin swager, make some really short full wad cutters to put on top of the shot instead of an over-shot wad.
-you probably won't do this, but Magnaporting will help the shot pattern.
-it's been a wile since I checked, but T/C made a screw-in choke for one of their barrels that would straighten out the rifling for shotshell use. If you are really gun-ho about a good shot patter, you may be able to have yourbarrel tapped to accept one of those. Oddlyenough, rifling isn't required to be spiral. Straight rifliing at the end will reduce the shot dispursion.
-Speer makes handgun shot shell cups. They will hold the shot toghether well. I have never tried one in a lever loader ... not sure if it would hold up to loading or stay in the gun under recoil. Maybe just load one cylinder with it and make it shot #1.
Personally, snakes don't bother me. I have two big ones in the living room