I think the same thing.
Any deer rifle will take out a T-Rex, because any deer rifle has plenty of power to smash a T-Rex knee joint. Then they are mostly immobile and you can pepper their central nervous system, lungs and vascular system at your leisure.
It might take them a few hours to die, but they won't be doing much more damage.
A few rounds to the spinal column in the neck should stop the thrashing about.
If you had an amazon robot and bear spray in your garage you wouldnt need your stuff in your closet for a t-Rex.