Actually the original post was: "Who is using a sabot in their sidelocks opposed to round balls or conicals , is this an option I need to try
Any advantages or disadvantages to using them
They are a .45 cl with a plastic sleeve correct ?
Any recommended brands or loads for a .50"
And I believe the advantages of a saboted bullet over a PRB has been beat to death in this post. If you want to keep it simple Brknarrow try some Hornady XTPs or a similar bullet in either .429" or .451" in weights from 240 - 300 gr. For the .429" bullet I would recommend the Harvester green crush rib sabot and for the .451" the Harvester black crush rib sabot. As for powder I would used either FFg black powder or Pyrodex RS and start at 80 grs and work up in 5 gr increments to find your rilfe's sweet spot.
When checking for accuracy be sure to swab between shots. You don't want a fouling buildup to give you a false reading.