The shotgun heavy is a heavy that appears in Army of Two: The 40th Day. It is first seen in Shanghai Streets, at the control room. They always carry the R870 and stand approximately 7 feet tall (making them taller than both Rios and Salem). They usually require a significant expendature of ordinance to eliminate and it is almost impossible to kill one instantly (can only be done if they are standing next to an explosive. They are notable for wearing extremely tough body armor that covers their entire body (except for their face) and they wear a helmet that is similar to what Corporals wear (but much tougher). Heavy Shotgunners will hunt you and your parnter down with single-minded purpose and not even bothering to take cover since they don't really need it, they will constantly advance toward you while firing their shotgun (and reloading when necessary). On top of that they sometimes operate in pairs and usually alongside a slew of Grunts and Corporals who will try to pin you down and allow the Heavies to get in close.
Heavy Shotgunners should be primary targets whenever they appear. They are absolutely lethal at close range thanks to their shotguns. They will execute you if they can get close enough while you or your partner are bleeding out.
It is best to use long ranged weapons and aim for the head it will still take close to 30 rounds from most assault rifles or sub machineguns to kill them, even powerful weapons like sniper rifles and shotguns will require 3-6 headshots to bring one down or an entire 12 round magazine from a Desert Eagle. It is still possible to kill them without shooting them in the head but it will take a large amount of ammo to do so.
Explosives will knock them down but will require a significant expenditure of ordinance to kill them (6-8 grenades from an MGL or 2 direct hits from an RPG!) If you need some breathing room, explosives will stun them long enough to get away.
If they do manage to get close enough to be dangerous make sure that you get behind something solid, switch to your most powerful weapon, and start blindfiring into the Heavy's face until he is dead. (The AA-12 works wonders in this kind of situation). Warning: don't even try to mêlée them; their armor is too tough and all you will get out of it is a punch in the face.
Perhaps the only remotely easy way to kill one is under the rare circumstances that you can bring a .50 cal machinegun or a gatling gun to bear against them. However, such instances are few and far between. A cheap way to defeat him is to escape him until he needs to reload and then empty a full magazine into his head to kill him off.