It proves rather ineffective against multiple moving targets, however. Overall, the Double Barrel is extremely potent at short or medium range combat with a single target. If you press E, your character will hold down their shotgun. It still suffers from a low ammo capacity, though. The change between ammo types only takes a second, making it a more versatile weapon in CQB than before.
With buckshot, the shotgun functions similarly to the Trenchgun, but at a faster speed.
Since the 0.53 update, pressing V will switch the type of ammo being fired, from slugs to buckshot and back. Using this weapon against more than one target will prove challenging for any player. It is best to use this weapon against only one target at a time, as you only have two shots before reloading. With slugs, it is very effective at a short-medium range. The Double Barrel shotgun excels at an one-on-one anti-personnel role.