I have the older t/c thunderhawk in 50 cal. I use the crush rib sabot with the hornady 300 xtp mag: bullets,I think they mic: in the ballpark .500
I like them and using 80 to 85 grains of T7 they shoot outstanding.
I can shoot the factory hornady black sabot but only if the barrel is clean otherwise they are a nitemare to get down the bore for a second shot if needed.
I also like the bufffalo 375 HPBT they also are undersized .459 another great shooting bullet in my t/c bore
I will tell you the hornady SST will not group at all in my barrel so it someting to play with to find the right bullet/sabot for each gun