Heckler & Koch Series

The Heckler and Koch GmbH series, or sometimes abbreviated as HK, is a family of guns manufactured by the German defense manufacturing company Heckler and Koch.

History
HK began operation after the end of the first World War. It's first office was the salvaged remains of a Mauser factory ordered to be destroyed by a French army commander. They originally manufactured various machine parts, but began manufacturing firearms in 1956.

Specs
The actual specs of an HK gun depends on the make and model of the weapon in question.

On Criminal Minds
HK guns aren't as frequently used on the show as SIG Sauers or Glocks, but several HK products have been used, mostly by unsubs.

HK guns featured on Criminal Minds

 * MP5A3
 * MP5A2
 * MP5K
 * USP
 * G36C