Lapua's 8x57 IRS case for double rifles, drillings and vierli ngs The 8x57 IRS case is the Lapua standard for breech brake combination guns like double rifles, drillings and vierlings. The 8 x 57 IRS is a rimmed sporting and hunting version of the German 8 x 57 IS military cartridge (also known as the 7.92×57mm Mauser). No matter what kind of game you are aiming at, the quality of...