.25 Caliber .257 117 gr. SBT. The 117 grain 1630 Spitzer Boat Tail GameKing bullet has a jacket produced by Sierra's unique four-station jacket draw process. This process produces jackets with maximum concentricity and uniformity together with uniform taper dimensions, resulting in bullets with extraordinary accuracy, dependable expansion, and deep penetration on medium game. The 117 grain 1630 bullet is best when ranges of shots are 200 to 500 yards.