If I read your post correctly; you bought .50cal hollow point bullets. Did you actually buy .50cal pistol bullets? Usually the bullets that work with sabots in a .50cal muzzleloader are around .45cal depending on what sabot is used.I would suggest after you get all of the above done ESPECIALLY DETERMINING THAT THE RIFLE IS NOT ALREADY LOADED; then go purchase some already set up bullet sabot combinations from a ML supply store or Walmart but do not try to make your own combinations until you know a little more. If it is a CVA as stated it will also accept and shoot Powerbelt bullets quite well. I also suspect the rifle is either loaded which is a definate problem until you correct it or it has a lot of fouling in the breech area which if Tripple Seven was shot is very likely as it tends to form a crud ring just forward of the load area.