RE: What sabot/bullet/powder should I buy?
If wanting copper, I recommend a 300 gr. bullet like Shockwave, XTP, Scorpion, Gold Dot, TMZ, Expander, SSTwith 777 loose powder. If wanting lead, Cabelas Dead Centers 300 gr., Extended Ranges in 300 gr. and Buffalo SSB in 375 gr.
Real blackpowder FFF, Goex Pinnacle FFFand Pyrodex P (FFF) would be my next three choices of powders.