Possible that you have a CVA, not CVI? If so, go to cva.com, and download a warranty manual for your rifle.
Yes, you may use black powder SUBSTITUTES, such as Pyrodex (and there are others) The subs are measured by bulk (volume) and not by weight.
Modern day muzzleloaders are not real high dollar rifles, but a lot of fun.
Only ways I know of to blow one up are (1) Use smokeless powder in a black powder only rifle, or (2) attempt to fire when bullet is not fully seated on the powder charge. A bullet halfway down the barrel will mess up you and your rifle, along with innocent bystanders.
Read, ask questions, enjoy.