sentences:  The second generation prototype of the Vector, called the K10, was announced at 2011 SHOT Show.It is a slightly more compact version of the Vector that is based on the same Super V system.The main difference is a redesign of the lower receiver intended for easy caliber interchangeability; utilizing just a single takedown pin, users can change between 9x19mm, .40 S&W and .45 ACP by mounting different lower receivers.