SIG Sauer’s new Copperhead pistol is a much abbreviated member of their MPX line. Chambered for the world standard 9mm Parabellum cartridge, it weighs in at 4.5 pounds without optic or magazine and measures just 14 inches with the stabilizing brace fully collapsed. Strip it down and poke around inside and you will notice it is a piston operated design. Most similar designs utilize a blow-back or delayed blow-back operating system. The use of a short-stroke gas piston system in a design like this has its pros and cons. The Firearms News staff has been running this one on the range, shooting out to 100 yards with no issues to date. Keep an eye on your local newsstand for a feature article on SIG Sauer’s MPX Copperhead slated for a future issue.