I'm trying to get ready to try a cowboy silhouette competition and need some advice. I'm using a 20" Rossi M92 in 44 mag. Boolit is a MP 432-640 that weighs 262gr with the small hollowpoint. I tried 7.0gr of Unique based on cowboy data I found on-line. 25, 50 and 75 yd results were fine. At 90 yds, they are unstable and I can't keep them on paper. Looks like I need a bit more velocity, but how much? I need a load that will reach out to 100 yds, but not be too hot for cowboy rules. Any suggestions for how much to increase the Unique charge?