Chain shotgun

The chain shotgun is a slightly heavier, multi-shot firearm in RimWorld which fires 3-shot bursts of rounds which deal a slightly higher amount of damage each; a moderate delay between each shot; a moderate time between bursts; very low accuracy and very short range. It'll take 3 shots to the torso to kill an unarmored human with a chain shotgun, or around 5 shots against a human with a normal armor vest. The chain shotgun can also instantly remove digits, cripple eyeballs and cause lethal brain damage if the victim's skull is unprotected. Limbs can be crippled in 2 shots against an unarmored human.

Since the chain shotgun has an extremely short range and fires in bursts - a quicker factoring in of odds with continuous failure - the chain shotgun can be considered a great weapon for inexperienced shooters, but not so good for skilled shooters; even the best shooters will struggle to be accurate with a chain shotgun and you're better off pairing them with longer-ranged weapons. A healthy level 0 traitless shooter, level 0 careful shooter or level 0 trigger-happy can somewhat efficiently use the chain shotgun up to 6 cells. However, a level 3 traitless shooter, level 0 careful shooter or level 6 trigger-happy is advisable to efficiently use the chain shotgun up to its maximum range of 9 cells.

On average, the chain shotgun is best paired with a careful shooter until level 5, then with a trigger-happy shooter beyond that point.

Melee Combat

A chain shotgun has a weapon bulk of 100%, but weapon bulk doesn't seem to have any observable effect on actual gameplay.

All possible melee attacks with a chain shotgun:

Tool	Attack	Damage Type	Power	Cooldown	Likelihood	Base DPS	Armored DPS
Overall	-	-	9.69	1.869s	-	5.181	4.767
Stock	Smash	Blunt	9	1.8s	31%	5	4.6
Barrel	Smash	Blunt	10	1.9s	34.5%	5.263	4.842
Barrel	Poke	Blunt	10	1.9s	34.5%	5.263	4.842

Obtaining

Chain shotguns can be purchased from outlander and orbital combat suppliers, or obtained from the following raider kinds:

Pirates:

Pirate - 3.9% chance (normal quality on average, 40-150% health)

Outlanders:

Town Guard - 1.9% chance (poor quality on average, 20-200% health)

Mercenaries:

Mercenary Gunner - 4% chance (normal quality on average, 70-230% health)

Spacers:

Space Soldier - 2.6% chance (good quality on average, 100% health)

Chain shotguns can also be crafted at a machining table once the gas operation research is completed; from 70 steel, 5 components and 45,000 ticks (12.5 mins) of work.

Conclusion & Comparison

The chain shotgun is a weapon that has an incredibly high base DPS, which in turn is offset by its very low base accuracy, meaning that it benefits greatly from high quality levels and being used against large targets. Alternatively, stray shots could also make it useful as a close-quarters crowd control weapon - though the minigun would likely perform better at this.

Due to its abysmal 9 cell range, the chain shotgun isn't a very feasible weapon for field combat since it's likely that people equipped with chain shotguns will get downed while trying to get in range with their target. With the above side-effects of using the chain shotgun though, it could be a very powerful weapon for holding chokepoints or generally having very close-up defence setups.

Going back to continuous failure: the chain shotgun effectively has a 78.4% accuracy from 0-4 cells, which then linearly increases to 79.9% at the chain shotgun's maximum range of 9 cells - the preceding figures of course being the chance of a single shot in the chain shotgun's 3-shot burst hitting a normal-sized target.