I've used 7828 with 84.5 gr and pressures are starting to get up there, any one ever used this bullet and get good performance with any other powders?

Does the rifle have freebore?? What brand of brass are you using. These are probably more key factors of what's happening. Not having feebore will probably have you seeing pressure 150 fps slower than with freebore. And rem brass can sometimes have the same pressure with about 3 grains less powder than weatherby brass. Mix these two combo's and you can really get some different outcomes.
None of my business but what are you using that bullet on?? It is extremely fragile for the speeds of the weatherby--not even up to par for penetration as the orginal hornady interlock.

Ditto what kraky said.

MRP From 77.0 grains to 84.0 grains
Federal 215 Primer

I'd avoid SSTs and for that matter Ballistic tips in the 300. Yes there are folks here whos swear by them, but at those velocities, even they admit, in a roundabout way, that they "pick" their shots ( as in avoiding the shoulder) in order to mitigate bullet failure. I've had real good luck with RL-22 and MRP, but you can't get MRP stateside anymore. jorge

I've had good luck with H1000 and the 165 gr. SST. It's one of the most accurate combinations I've used in my .300 Wby. Sako. It's considerably slower, however, than some other loads, but with this particular bullet, that's a good thing.

I've used this load successfully on whitetail deer, but I do try to avoid the shoulder, which is something jorge alluded to. With faster loads using powders like RL22, 7828 or H4831, I like a stouter bullet. The 168 gr. Barnes Triple Shock is my favorite.

i'm usiing norma brass, and its for an antelope hunt this fall, i don't want to use anything lighter than 180 gr. even though it would be more practical for antelope.
this rifle really groups 200gr. accubonds. but i wanted something a little lighter and something not as tough since it has the bonded core