Here is the Assault Shotgun from GTA V.

V2 - fixed decals

If you want to follow my weapon converting program, you must add it to the game with the Ryosuke's Weapon Limit Adjuster (http://hotmist.ddo.jp/plugin/wlimit/wlimit04.zip)
After that, follow the istruction in the readme for installing it.
[ALL MISTERIX 4 WEAPON RELEASED IN THE PAST NEEDED]

Credits:
Ryosuke, for his Weapon Limit Adjuster
Automan, the creator of Misterix, for his help with some stuffs
arthuros mazonakis, for decals fix