Years ago my grandfather gave me a muzzle loader. It is a .30 caliber, has an octagon barrel, twin triggers, and says Riddle in scroll on the side of it. All the metal parts have the same part number #28 on them. I have a few of the original caps and balls, the wooden rod, but not much else.

I was told by a pawn dealer probably 40 years ago that it was made in Pennsylvania around 1860, and wasn't worth much.

Does the Riddle name mean anything to anyone?

Try contacting the National Muzzle Loading Rifle Association. Their publication "Muzzle Blast" has a colum for questions such as yours.