Neck Shots loads

[colonyfirearms]

I only get to deer hunt after work. About 2 hours a day.
One thing I don't want to do is shoot one and have to try to track it in the dark.
So I am thinking that if I do neck shots then it is miss or down. I loaded some hollow points for fast expansion thinking this will make the neck shots more productive. 7mm rem mag. 160gr HP solid copper 60 of 4831SC
So far I have taken 2 and it worked, both at around 150 yards dropped in tracks.
But I have not been happy with the expansion. If I hadn't hit the neck bone there may have not been any expansion.
Last nights 4 point exit was about 1" diameter.
Any suggestions?