Blaser, in partner ship with Norma, will be introducing a new line of magnum cartridges later this year. They are not giving out any detailed information until May, but they have said these are completely new cartridges, not based on any previous designs.
7mm Blaser Magnum, .300 Blaser Magnum, .338 Blaser Magnum and .375 Blaser Magnum
Factory cartridges will be sold by Blaser and Norma and will be available in August along with Blaser R93 rifles chambered for them.
More info here.