The 300 H&H; Flanged NE is a rimmed version of the 300 H&H; Magnum, designed for use in double barreled rifles called the .30 Flanged Magnum. This is factory loaded to lower pressure than the rimless version of the case, resulting in a MV of only 2575 fps and ME of 2653 ft. lbs. with a 180 grain bullet. Today this cartridge is pretty well obsolete, as double rifles have been adapted to the .300 Belted Rimless Magnum. 

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