Federal Premium, 7MM Backcountry, 155 Grain, Terminal Ascent, 20 Round Box P7BCTA1 The next-generation, one-piece design allows higher velocities over modern brass case ammunition. And because the cartridge is dimensionally smaller than its closest brass-case counterparts, 7mm Backcountry achieves these ballistic advantages through smaller rifles and with an extra round in the magazine of most platforms. In developing 7mm Backcountry, Federal's team of engineers set out to design a cartridge that answers a market need that seemed unsolvable-magnum velocity out of shorter barrels without increasing recoil. They did, but in the process they produced true innovation, creating a new way to make rifle ammunition faster, flatter shooting and more powerful.