Well you can't kill a deer too dead.

Having said that it is way way more gun than is needed. Heck, so is the .270 and 30-06 for that matter.

IMO a 150 grain ballistic tip type of bullet at 300 magnum velocities is a bit "explosive" on big game. I would prefer to use a bullet like the accubond which will give you a good mushroom for a wide wound chnnel through the chest but does not over expand and cause a ton of meat damage. Other good bullets for magnum velocities would be a TBBC, A-frame, Nosler partition, Barnes-X, Failsafe and still more. Of course none of these premium bullets is actually needed for deer size animals but if meat damage is of a concern to you they will damage less of it.