Remington 9 1/2M Large Rifle Magnum Primers are engineered for shooters who demand unfailing ignition in extreme environments. Each Remington 9 1/2 M primers is rigorously tested from –20 °F to +150 °F, guaranteeing dependable spark whether you are glassing mule deer in sub-zero winds or hammering steel in blistering summer matches. The hotter flame front reliably lights slow burning magnum powders, stabilising velocities in big-bore cartridges like .300 Win Mag, .338 Lapua, and hard?hitting .375 Ruger.