I have 4 topper 30-30s. 3 are shorties and one was my grandpas, so not hacksaw nor carbide will ever touch it.
I don't know anything about cast, but I can tell you that all of mine like 150gr Hornady SSTs. And, they all LOVE 125gr Nosler BTs. I just bought some 110gr Barnes X to try, but only out of boredom. The 125 BTs under a max load of H335 print .5 to 1 MOA 3 shot groups in all 3 shorties, and the full length clover leafs 3 shots all day long.
Topper 30-30s are the source of my NEF/H&R lust. You will love it!
Steve