There are 4 types of shotgun ammo in CE:
- Slug, a single heavy projectile.
- Buckshot shell, contains lead balls shot as a tight spread of 9 pellets.
- Beanbag, less-lethal round, contains a fabric bag packed with lead balls.
- EMP round, delivers an electromagnetic pulse on impact.
Slugs are useful for short-medium range engagements, they are good against tribals, early pirate raids and animals. You're better off using other weapons with AP ammo against later pirate raids.
The buckshot is useful for crowd control as it is capable of hitting multiple enemies. It is devastating against tribals, early game pirate raids and animals. It becomes a bit obsolete once pirates start wearing body armor or start taking ballistic shields with them. It is not recommended to be used against mechanoids, as the buckshot will just ricochet off its armor. You are however able to hit certain vunerable spots with it, such as the sensors, fingers, blades and the chemical analyzer.
Since the beanbag shell only does low amounts of blunt damage, it is not recommended for killing people. It can be used to stop berserk pawns from doing too much damage or stopping pawns that are having a tantrum in their tracks, it is also useful for capturing raiders as there is no bleeding to stop. It can also be used for hunting, as it has a very low chance of destroying body parts, which increases the amount of meat you get from butchering. One should be careful when hunting for the larger animals with a higher revenge chance though, as one or two shots may not incapacitate it, which leaves room for it to attack.
Extra: As of CE 1.4 Beanbag shells are capable of downing mechanoids, but it is very risky to pull off. If you're able to get muscle spasms to 'severe' level on any mechanoid, it will fall down and become incapacitated. Lancers will drop their ammo, making them mostly harmless. And centipedes will also drop its ammo, but if it manages to recover from the muscle spasms, it will still attempt to kill enemies near it by ramming them. Scythers will just become incapacitated and stand up later. This does not seem to be an intended behaviour and may be patched in later versions.
EMP shells Edit
It is an excellent choice against mechanoids, if you manage to hit a mechanoid with the EMP shells, it will stop in its tracks and shut down for a few seconds, which turns it into a big, non-moving, defenseless chunk of steel. Untill it reboots, that is. It also causes electric burns on hit. The shells are also capable of temporarily shutting down turrets. But you're better off using other EMP rounds as using a shotgun means getting very close to a turret, (16 tiles away from it.) which could give defenders a chance to suppress your pawn and maybe even incapacitate it. If you manage to hit a turret however, it will be disabled for about 7 seconds.
It is recommended to swap to any other shotgun ammo when fighting humanoids, as EMP shells will cause electric burns which only do minor damage to them.
Real life equivalents: