Here are some of my 45-70 bullets that I shoot.
left to right
150gr JRN .308 far left for standard
300gr Spitzer Alpha Lafrank
300gr Hornady HP
350gr Swift A-Frame
405gr Beartooth GC
405gr Spitzer Alpha Lafrank
425gr Beartooth WLNGC
430gr Cast Performance WLNGC
450gr Barnes TSX
550gr Jae-Bok Joung "Crater" WLNGC
525gr Beartooth WLNGC

If you want to stick to cast I would recommend a 425gr WLNGC Beartooth Pile Driver or a 430gr Cast Performance WLNGC's Jae-Bok Young makes an awesome bullet called a Crater that I would also recommend.
My bullet of choice after using all of the above loads and many more is the 350gr Swift A-Frame.
