There exists slightly less than two cents worth of difference in the performance of various .30 caliber magnum cartridges, which might explain why we don't hear much about the Normaversion anymore. But it wasn't always that way. Back in 1960 when Normastarted shipping unprimed cases, chamber reamers, and chamber drawings to American gunsmiths, its future looked bright. At the same time the .300 Weatherbyand .300 H&H; were the only .30 caliber magnum cartridges available and both were too long for the ship loads of cheap '98 Mauser and '03 Springfield actions floating around during the golden age of mail order firearms. In addition, Winchester's short magnums in .338and .458calibers were beginning to take off down the path of success. So, Norma's short .30 caliber magnum fit right into the scheme of things. For awhile the Swedish cartridges future looked promising, but then came the .300 Winchester Magnum. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.