Hornady Superformance, 260 Rem, 129 Grain, SST, 20 Round Box 8552 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.