Hornady Superformance Ammunition, 7MM Rem, 139 Grain, SST, 20 Round Box 80593 Increase your rifle's performance up to 200 fps without extra chamber pressure, recoil, muzzle blast, temperature sensitivity, fouling, or loss of accuracy. Superformance(R) uses progressive propellants that take your favorite V-MAX,(R) NTX,(R) SST,(R) GMX,(R) InterLock,(R) and InterBond(R) bullets to levels of performance that are simply unattainable with conventional ammunition.