Don:
If you find a mold to make conicals for your .31, remember, even if they are made out of pure lead they will be considerably harder to load into the chambers than a round ball is.
This is true with all conicals when they are used in revolvers because they have a much longer length of lead that will need to be sheered off of them than a round ball does.
The conicals that are made when using the brass molds that come with some cased pistols have a "heel" on them.
This slightly undersize area fits freely into the chamber and serves as a guide for the bullet while ramming it into the chamber.
Speaking of these brass molds, Dixie Gunworks sells a little brass one that makes both a round ball and a bullet for the .31 caliber guns.
These are made for folks who want to create a "cased pistol" like Colt sold.
Their part number for this is CA0901, but beware.
They say in their catalog text:
"Does not cast perfect balls or bullets; most are undersized- can be used for plinking but will not be good enough for competition shooting. Recommended for cased pistol and revolver sets..."
The price in their 2008 catalog was $29.95.