Heckler & Koch MP5A3

The MP5A3 is a submachine gun designed by Heckler and Koch.

History
The MP5A3 was created through a series of firearms created by HK in an attempt to replicate the success of their G3 rifle. When it was first created, it was titled the HK54. The MP5A3 was further expanded upon in 1964 and finalized in 1966, where it was adopted by German forces.

Specs

 * Cartridge: 9x19mm Parabellum, 10mm Auto, and 40 S&W
 * Action: Roller-delayed blowback and closed bolt
 * Weight: 6.8 Ib. (3.1 kg.)
 * Length:
 * 27.6 in. (700mm.)
 * 21.7 in. (550mm.)
 * Barrel Length: 8.9 in. (225mm.)
 * Capacity: 15-100 rounds

Non-Criminal
The following non-criminal characters use/used MP5A3s:
 * Season One
 * SWAT officers - MP5A3s are frequently used by SWAT officers throughout the series, starting in "Extreme Aggressor".
 * Season Five
 * Derek Morgan - He used an MP5A3 in "A Rite of Passage".
 * David Rossi - He used an MP5A3 in the same episode.

Criminal

 * Season Eleven
 * The Virginia Anarchists ("The Storm") - Several members of this group used MP5A3s.