Shotgun

The Shotgun is one of the three weapon upgrades available when you reach level 10. It has the shortest range for all the guns but does tons of damage if someone gets close, making it useful if lots of people try to get near you.

Countering
Shotguns can insta-kill you at close range. To defeat a shotgun, use either a pistol, a sniper, or an assault rifle. They can be used because they have a longer range than the shotgun. Be careful when you try to defeat someone with a shotgun though, because they might suddenly head towards you and get closer, allowing you to get in shooting range, in which most likely you will die, unless you have a barrier perk to block the person and gain some distance. Assault and sniper rifles are extremely effective as a shotgun user cannot hit you unless they get close and when they do you can shoot them before they even can reach you. Even if they kill you, they will end up taking massive amounts of damage.

Using
Get near teammates that don't have a shotgun, especially snipers. They can protect you because they have a longer range, and you can save one another. If someone is shooting you from a distance, your teammate can kill them. If someone gets too close to your teammate and they can't shoot, you can kill them quickly with your gun. The best way to use this is if your teammates are trying to claim middle (Point A), there might be a ton of bullets and a mini war. Get in you teammates and blend in with them, occasionally going out to kill the other team. Do not chase them, as they might have a longer range and can kill you.