YOUR guns may be different than MINE, but I use Wheel weight for loads to about 2000 FPS in several calibers. Lube and bullet fit are the most important things to look at when loading cast. One load will work very well in one gun and lead another for SOME reason. IF (big IF) the mold design calls for a gas check ,I use one.You may have to go to a harder alloy ,such as Lyman#2, to get highest velocity in your guns. Remember that revolvers and the Contender are different in that there is NO barrel/cylinder gap. Another thing is the difference in throats of the cylinders have to be considered. A HARDER bullet MAY cause more leading than a softer one.This is due to harder bullets NOT being able to "slug up" to fill the bore! In short, use wheel weight to start and work up to linotype for a really hard bullet IF needed.