For White Tail Deer both the 444 and 45/70 will kill them dead.
Both guns are overkill for deer, especially woods hunting. Most
are shot under a 100yds. Either rifle will kill deer with any bullet
that is accurate in your gun. A cast bullet will get the job done
deer are not that tuff. All you have to do is make a decent shot.
I use 300gr Hornady JHP in 45/70 and 240gr XTP in 44 mag.
Locals are using same 240gr XTP in their 444s with sucess. If
you are shooting bear or hogs you may need a harder bullet.