In American Pioneer Powder I would not buy the FFg grade only the FFFg grade. The FFg grade is like shooting fish tank gravel. The FFFg is a better grain size and will work just fine in your CVA rifle. I shoot 3f powders almost all the time in my inlines and in most of my side locks. There are always exceptions but not many.

The FFg in fact is so course, I had a hard time getting it to pour out of the powder horn. So I took a plastic ketchup bottle with a plastic lid, and drilled the hole in the top bigger so I could pour it into my measure.

Get the FFFg (in my opinion) and just be real careful about moisture. I personally have not had a moisture problem with it, but some posters who's opinion I respect greatly claim they have....