A 300magnum isn't going to drop 'em any faster ... I can vouch for that!
The front nose section of the Partition expands very quickly and does lots of internal damage, but then the mushroomed bullet ends up not much bigger than the original bullet size and you end up with a small exit hole. This is how they work, but they practically guarantee an exit hole. It all depends on what kind of performance you want. You "might" be able to use a regular soft nosed bullet (ie. Hornady, Speer, Rem, etc) and get a bigger exit hole, but they will not guarantee you an exit.
My Dad has had great results with 140gr Partitions in his 7-08. I'm trying 130, 139, and 145gr soft points in my new 7-08. I have no experience with them on deer yet. Personally I would stick with something less than 150gr since the velocity starts to drop off pretty quickly with heavy bullets and they really won't gain you anything as far as damage goes. They are actually more likely to just pencil thru than something in the 140gr range with a higher impact velocity. Maybe one of the new "bonded core" bullets coming out this year will do the trick ... expansion plus weight retention.
Good luck ... Crayfish