A 308 can take down any animal in North America as long as you can place the bullet in the right spot. And yes a 150gr bullet is perfect for deer and it can kill elk and moose too but if you are uncertian go to the 180gr.And a 308 is no where close too small for anything, like you can kill elk and moose with a bow can't you? so I would think a 308 can do the job just perfect.