I would suggest the 200 grain accubond. It has a .588 BC which means it shoots about as flat as most 180s at long range and hits a lot harder.

Most Weatherbys have lots of freebore and also allow long OAL cartridges to feed from the magazine. So you can seat that long accubond out of the case without getting into the rifleing or taking up powder capacity.

2900+ FPS should be doable with that bullet and any of the RL22, 25, or RL17 powders. I think best velocities are with Power Pro 4000 according to Alliant.