Kevin,
Most home-made pistol shotshells are only marginally effective for pests and snakes up close. Anything beyond about 10-15 feet is pretty safe. The limiting factor is the small shot payload and the barrel rifling which ruins good shot patterns.
The best available store-bought shotshells are those by Speer in .28/.357 and .44 Magnum. They also make the blue shot capsules for reloading.
If you really want to make pistol shotshells that work, you have to go to custom cylinder-length cases to hold more shot.
In the .44 spl/mag, I use cut-down-.444 Marlin cases with Unique powder, a 1/4" cardboard wad column, and fill the case with #9 shot. A thin card wad and a drop of candle wax and heavy crimp holds it all in. Size in a .41 Magnum sizing die until the case chambers in your revolver.
In .45 Colt, a large rimmed rifle case cut down and necked with a .44 Mag sizing die works. I've used .303 British cases and even .45-70 cases swaged and with the rims turned down in diameter.
In the .38/357, finding a suitable case long enough is a problem. I've not found that size bore to be very useful for shot.
For all these loads, work your powder charges up SLOW and EASY. Start with a modest powder charge suitable for a wad column and shot charge weight equal to a lead bullet of that weight.
Test fire your loads for pattern, and not for velocity.
HTH
John
