First off. The manual is wrong. It's an old subject that's been talked to death. Use 25 gr of either Pyrodex loose powder, or T7. The T7 load will have more power, but both loads are safe. You can't use pellets, or BH 209.
Good luck with your new gun. I love C&B revolvers, and have been shooting them for 30 years.
btw..You can also use real black powder like Goex, Swiss etc. If you can find it. It's a little messy, but it's authentic if that matters to you.