I guess that depends on the answer somebody would give you.
You might say that cast isn't a true monolithic, because it will slightly deform when it hits hard bone. It will go right through it if it is a good hard cast, but you will make a dent.
Now if you are talking about monolithic solids that have a tungsten core surrounded by hardened copper, then you aren't going to find much that is going to bend it. I never found a need to buy such an expensive bullet, espcially with the power my bigger guns put you. I would trust a performance cast 405 grain wfngc up against anything around with my .458 lott. If I am looking to shoot an elephant and get a full pass through, maybe I'll look for one of those hard metal super bullets, but not yet.
I spend too much money on barnes x-bullets in my mid bores to have to buy lead-free in my other guns!