revolver cylinder

I apologize if this question is simply answered, but I did a fair share of searching and can figure it out. I'm thinking of getting a colt 1851 conversion in 38sp. Because because I'm getting it for no other reason than to have fun and look cool I may use my already established reloading setup...

I have a S&W M19-6 that used to shoot 99s at 25yds on a steady basis. It recently started to spray all over the target with odd sideways impacts, with either my handloads or factory ammo. I cleaned the barrel and chambers with little to no effect. I shot my handloads in another revolver and...