The S2 AM sniper rifle fires 14.5x114 millimeter armor-piercing, fin-stabilized, discarding-sabot rounds from a 4 round magazine.  Based upon the specifications of modern APFSDS rounds used by main battle tanks, I assumed a penetrator diameter of 3.02083 millimeters and a length of 63.6548 millimeters based upon a 25 to 120 diameter ratio and a 550 to 985 length ratio in the APFSDS used by the M1A2 Abrams.  I also assumed that the penetrator was nearly cylindrical and that it was composed of nearly 100% depleted uranium.  With the above assumptions and with the fact that depleted uranium has a density of 18950 kilograms per cubic meter, the penetrator has a volume of 4.5622x10^-7 cubic meters and a mass of 8.645369 grams.  Combining this with the fact that the kinetic energy is between 90.44 and 203.44 kilojoules, the muzzle velocity of the S2 AM sniper rifle is between 4574 and 6860 meters per second.