I want to know.
CB Percussion is a company that makes percussion instruments (mainly drums).
Yes. It is a valid substitute for black powder.
a rifle cap.
1800
If you have the money.
It should be a #11 cap.
your rifle is a percussion rifle from the civil war in 58 caliber. value depends on overall condition. estimate plus or minus $500
Seek a professional appraisal
depending on condition, $100-$150.
You need the services of a gunsmith
Because it makes it's sound by being shaken or struck. That is the definition of a percussion instrument.
The correct spelling for the instrument is "percussion."