Here was the rough gist of it:
This is not as hard or expensive as you think
Your first holster may not work out but you'll learn something and the next one will be better
Overall things to remember:
All leather will interact with metal if humidity and water is allowed into the mix (even just humidity changes in a room. )
Tanning: Vegetable tanned (Oak bark and etc) is not as corrosive to metal as chrome-salts tanned.
Cleanliness: Leather will pick up oils and fingerprints and fingernail marks, etc... that will really show when it's dyed. Wash hands and keep the work surface clean.
a good leather treatment will keep the water from the leather. There's a product called Aussie something that they recommend. Treat the inside AND outside of the leather.
Basic construction:
Fold a sheet of stiff paper in half. Lay the gun in with its centerline on the crease.
Lay it over in the appropriate direction (think how you want it it ride). Trace the gun. (Keep the pencil straight up and down.
Trace another outline 1/4 to 3/4" outside that. This is probably the minimum leather size to get it formed.
Now add any shaping / flanges / etc outside the forming line.
When you cut the leather, give yourself an extra inch outside any lines you have drawn (it's easy to trim, it's not so easy to add on leather
)
Wet the leather front and back with a damp sponge
make SURE the gun is unloaded.
Wrap the gun in plastic.
Place the gun in the appropriate position and fold the leather over.
Make sure the orientation is going to be correct.
Work and form the leather as you want it.
When you're happy with the shape, figure out where the stitching is going to go and mark it on the leather.
Use a tool to gouge out a line for the stitches to lay in
Use a tool to mark the stitch spacing
Punch holes and stitch as you go.
Use waxed sinew to stitch. It will hold the stitch without the need for knots.
You probably want to practice this on scrap a bit.
The stitch is a cool figure eight and if done on a stitching pony you can do a cool stitch where you're effectively tying a knot inside the leather.
When you reach the end, stitch back 4 stitches to hold.
Cut off the stitch on the back side
Final trim of piece
Bevel edges
Burnish and shine edges
Dye the piece
Treat the piece
Wear it proudly.