50? Are you afraid your moose is going to be driving an armored car?
Seriously, while the .50 has legitimate use as a long range sporting arm.. the there is a HUGE difference between SHOOTING a moose, and hunting one. Your shot will likely be up close and personal (within 100 yds)
A solid 375 H&H magnum by CZ is more than up to the task, as far as busting brush and breaking bones.