The addition of "wet" hardpoints meant the F-100C could carry a pair of 275 U.S. gal (1,040 l) and a pair of 200 U.S. gal (770 l) drop tanks. However, the combination caused a loss of directional stability at high speeds and the four tanks were soon replaced by a pair of 450 U.S. gal (1,730 l) drop tanks. The 450s proved scarce and expensive and were often replaced by smaller 335 US gal (1,290 l) tanks. Most troubling to TAC was the fact that, as of 1965, only 125 F-100Cs were capable of utilizing all non-nuclear weapons in the air force inventory, particularly cluster bombs and AIM-9 Sidewinder air-to-air missiles. By the time the F-100C was phased out in June 1970, 85 had been lost in major accidents.