I have been shooting my CVA Kodiak mag for the past 1 1/2 years and like it. As far as bullet and powder combinations, you need to check your states regulations. Here in Colorado we can only use loose powder and conical bullets. Here is my current load.

85 grains of Pyrodex P (3F) max load for my rifle.
370 grain T/C Maxiball
Remington Kleenbore 209 primer

Make sure you read the owners manual VERY well. You cannot shoot more than 400 grain bullet in a conical and I belive no more than 300 grain bullet in a sabot. No more than 100 grains of 2F powder loose (150 if you use pellets). I switched to 3F powder, but 85 grains is max.

Overall I like the rifle. It's easy to clean and shoots well. If I had to do it all over again, I would probably spend just a couple of extra bucks and purchase the T/C Omega .50. I think that would be money better spent. Just my .02. Good luck and enjoy whatever your choice may be.