Complex sentence: Colt followed this up in 1992 with the "Colt All American 2000", which was unlike any other handgun Colt had produced before--being a polymer-framed, rotary-bolt, 9x19mm handgun with a magazine capacity of 15 rounds.
Split into simpler sentences: Colt followed this up in 1992 with the "Colt All American 2000", which was unlike any other handgun Colt had produced before. The Colt All American 2000 was a polymer framed, rotary bolt, 9X19mm handgun with a magazine capacity of 15 rounds.