The Double Barrel is an uncommon shotgun found at civilian locations and Farms. It uses Buckshot and Slugs for ammuniton, which can be made by crafting Shells with two nails for buckshots or two bolts for slugs.
The Double Barrel has the highest damage-per-pellet of any shotgun, and has the potential to deal the highest damage-per-shot of any weapon in the game. If the pellets all hit their target, or if you use a slug, the shotgun is able to deal 240% damage.
It can use two common types of ammunition (buckshot and slugs) for different purposes.
It has a very light weight, and is the second-lightest firearm in the game, next to the Magnum.
It can take down players up close with armor in one hit; making a starter player have safe access to player loot.
Unlike other shotguns, when aiming down the sights and shooting, there is no recoil from the shot.
Disadvantages
The Double Barrel has a sluggish rate of fire.
Like all shotguns, it has a very short effective range.
Also like all shotguns, the damage it deals is dependent on the number of pellets that hit the target, meaning that while it has the potential to deal a massive amount of damage, it also has the potential to deal next to none.
It is only found at three locations.
It has a meager capacity of 2 shells, and loads them one at a time.
It does not allow barrel attachments.
Trivia
The 2 barrels don't actually open up when reloading, making the process otherwise impossible.
A double barrel is a shotgun with two parallel barrels, allowing two shots to be fired in quick succession.
The Double Barrel is a sawed-off shotgun, evident by its very short barrels and lack of a stock. It appears to be in the Lupara style.
In version 2.0.3, it can be found in the S.S Haven cargo ship, along with every farm-exclusive item.
and Slugs 
for ammuniton, which can be made by crafting Shells
with two nails for buckshots or two bolts for slugs.
