Not having tried a Contender barrel, I can only offer suggestions. Blue Dot, or HS7, may be the way to go. Have had good success with Blue Dot in both. Start low and work up as there seems to be more lot to lot variation with Blue Dot. BD burns well in a .45 Commander with 8.6gr behind a 230gr cast, but the same load leaves unburned grains in a Colt SAA. Yes, I said single action; aftermarket Christy cylinder. In a Navy Yellow Boy .38 Sp, a 158grRN cast ahead of 7.3gr BD is great, but it is a plusP load. Several manuals list these along with Ken Waters' Pet Loads. Ken used it in a number of rounds. Again, work up. BOL.