As with any cartridge, magnum or not, follow the load data, it will indicate whether or not a magnum primer is needed for any particular powder. The fact that a cartridge is named a "magnum" does not indicate which type of primer is necessary, it's the powder that determines that, or rather the specifics of the published load one uses.
I do know that H110 and 296, which are both the same powder, require a magnum primer. And also, if you use H110 / 296, don't reduce the charge to less than the published starting charge.
Always follow the published data as it is expressed.
GS