I hunt deer with both a Ruger Redhawlk 7 1/2" 44 mag and a Ruger Super Redhawlk 7 1/2" 454.
Shot placement is everything .
True if you shoot Hornady 240 gr 454 load the shock of the 2000 fps bullet is greater than a 1400 fps .429 di bullet but the dead deer will not know the diffrerance.

If you load the 454 is more versital.
I load 45 colt cowboy loads and shoot it out of my 454 to the 360gr hardcast load at 1500 that I hope to use on bear next year.

I load a 250 gr Hornady bullet at 1450 fps for deer .
It is just a little faster than you can push a 44 mag bullet.
Off sand bags sub 3" groups (great for me ,gun & load shoot better for others) at 100 yds.

Witch ever you choise it will kill deer to at least 100 yds cleanly.

Have fun ,shoot lots and get good at killing deer