I'm going to need a bigger gun

"plinker"I let this one walk, but what would it take in an air rifle for a beast of a whitetail like this? I'm assuming only a through the brain shot -tricky. Watch closely and you'll see the piebald whitetail he just fought. The doe already past to my left. 
https://youtu.be/3UE7u-ys3Nw​
Deer are soft, a .45 or .50 cal air gun with decent power will take it down no worries