I have loaded a fair amount for the .300 SAUM. My favorite load - which has been developed for Elk but would be perfectly suitable for Moose is as follows:

Barnes 168 gr. Triple Shock
46.5 grains of Varget
Winchester WLRM primer
Cartridge overall length 2.82
Chronographed velocity - 2975 fps
Groups .75 at 100 yards

This is a nice accurate load with plenty of kill power for Moose.

If you are not familiar with the Barnes bullets, take a look at their site. You can easily go a bit lighter on bullet weight due to the weight retention of their copper bullet design.

Good luck.