There are many things that enter into the answer to your questions.If you can measure your bore dia. it is easier to find answers. my Omega has a bore of .500 crush ribs are to loose and won't group the HPH24 fit nice snug but fairly easy and shoots good,to load the HPH 12 is to tight shoots ok but a battle to load the SW is a bit tighter than the 24 but not real bad to load and shoots good,also try both the 451 and 452 to see what fits best in the best fitting sabot and remember to loose wont shoot good, I would start out with black FF or Pyrodex RS loose powder as they are stable in more guns than any of the newer powders, then after finding a sabot and bullet combo that fit well try different bullet weights and styles when you have a bullet and sabot that you have confidence in; try other powders to see what your gun prefers. Also there are some people who believe in certain products or are paid to push them keep your mind open and do your own thinking. Lee