I would just be guessing,, but since I shoot 140 grain head,, and have killed a large buffalo with one,, I know a smaller head is effective on all size game,,
ok that being said,, to shoot a 400 grain head,, would take a pretty stiff spine arrow,,
and on a heavy bow,, wow where would you get a shaft to work for that,,
so I would guess that the head and shaft gonna weigh 1500 grains, just guessing,,
I would say a 80# bow would handle that at deer killing range,,