Super Vel's "Certified Select" Training Ammo is re-manufactured with once-fired brass casings on the same equipment and with the same components as our premium "yellow box" line of factory-new brass casings. This load duplicates the original Mk 144 Mod 0 subsonic 9mm ammunition that Super Vel made for the U.S. Navy SEALs in 1967. The load features a 158 gr. FMJ bullet at a subsonic velocity of 965 fps, which replicates the recoil impulse of standard 9mm ball so that a pistol can be fired suppressed with the factory-original recoil spring (and not have to substitute a reduced-power recoil spring). Super Vel's original Mk 144 Mod 0 ammunition was used by the SEALs with their Mk 22 Mod 0 "Hush Puppy" pistol, a highly modified S&W Model 39 with a slide lock device to prevent the sound of the slide cycling.