Statjunk; What chambering is this? I've read that you are limited to your OAL because of your magazine. So that restricts you with playing with the length too much. If you are shooting the 30-06, I've had good luck with IMR4064 powder and 180 gr bullets. My '06 shoots the 180 Barnes TSX and Sierra Game Kings well with 49 gr of IMR4064. This is pushing max so back off some at first.
Personally, I've never had any luck getting Partitions to shoot well for me. Ballistic tips - definately. Same for Hornady SSTs. These shot like crap but the old Interlocks did well.
In my 300 Win Mag - I had good results with IMR4350 and 180 gr Accubonds.
But in my opinion, If you got a good shooting load with your Speers and Sierras, you don't need to mess with any others. These 2 will kill a bear provided you do your part