Pick which ever cartridge you like both rifles will get it done. I have both so I know. For what it is worth a Mark X Interarms is a clone of the FN commercial action which evolved from the clunk M98. Don't call it a 98 it isn't one.
I’ve been scolded for calling them Mausers before, but never 98s😜. My Heym is a true 98. Only departure is the bolt handle, which as far as I can tell, was manufactured bent for scoping. Floorplate has the hole for a bullet nose, there’s a clip guide, wing safety, thumb cut, and C-ring. Published info on Heym that I’ve found generally starts when they began making rifles for other companies, and then similar models sold by various department stores.
