165 grain is enough for any animal. We use 180 grain bullets more for moose and bears. It is more than enough for any deer at any distance you can ethically shoot.

I have used a 150 grain bullet. Just be sure it is well constructed as it will be moving very fast. You do not need a heavy bullet for a small animal of 20-40 kgs.

Cheers,

577500WR
(Matt)