Benelli M4 Super 90

The Benelli M4 Super 90, also known as the M1014 JSCS, is a gas operated, semi-automatic combat shotgun currently used by Takashi Komuro in place of the Ithaca M37. While it is heavier than the Ithaca, it is more efficient in combat.

Plot
Acquired on Chapter 27 when Kohta Hirano opened the evidence stockroom to look for ammunitions and guns, and tells Takashi to use it

Trivia

 * As what Kohta Hirano said, it was basically used by the US Marines and British Army, it is heavier but its easier to use in combat because of its semi-automatic, gas-operated action. It is known in both services as the M1014 JSCS (Joint Service Combat Shotgun) (USMC),and L128A1 (British Army).
 * The Benelli M4 appears to be equipped with a Trijicon RX01. If that is the case then it shouldn't have been affected by the EMP due to using tritium to absorb light to illuminate it's reticle.