I don't think they even make them anymore. Sorry.
don't believe any such item as 58 cal. black powder pellets. but, there is a 58 cal. slug for the 58 cal. black powder rifle
First, find a copy of the owner's manual for YOUR pistol. Second, use ONLY black powder, or a modern black powder substitute, such as Pyrodex. The ROUGH rule of thumb is one half the bore diameter in grains of powder. A .32 cal would use ABOUT 12-16 grains of powder.
Dikar Spain-45 Cal black powder only
Either FFFg black powder or Pyrodex P may be used.
No
How much is a old black powder only 45 cal long barrel pistol worth?
yes
what is this rifle worth?
Take it to a gunsmith. That is what they do.
Follow the recommendations in the owner's manual.
110 any more you just blow power out of the muzzle.
Most recommend is 3F powder, either true black powder or the "synthetic" or black powder substitute equivalent and between 25 and 30 grains should due nicely.