Should it be possible to make a suicide? I haven't seen this mentioned in the rules (though I admit that my edition is old), and would like to go with the "everything not prohibited is allowed" principle.
There are very few situations when this is actually meaningful, but let's make one example.
Suppose there are three players left: a deputy, the sheriff and a renegade, in this playing order. The sheriff and the renegade each have a mustang and a long-distance weapon, otherwise no one hasn't any cards at all in hands nor in play. Each of three players has only one bullet left.
The deputy draws two cards, they are a bang and a general store. Bang is obviously useless so he plays the general store, revealing three bangs. So now we know that each player has a bang.
Now, if the deputy ends his turn, the sheriff may kill any of the two, giving a 50 % chance to win the game; if he guesses wrong, the good guys will lose. However, if the deputy plays a bang on himself, effectively killing himself, the sheriff may surely kill the renegade.
There are very few situations when this is actually meaningful, but let's make one example.
Suppose there are three players left: a deputy, the sheriff and a renegade, in this playing order. The sheriff and the renegade each have a mustang and a long-distance weapon, otherwise no one hasn't any cards at all in hands nor in play. Each of three players has only one bullet left.
The deputy draws two cards, they are a bang and a general store. Bang is obviously useless so he plays the general store, revealing three bangs. So now we know that each player has a bang.
Now, if the deputy ends his turn, the sheriff may kill any of the two, giving a 50 % chance to win the game; if he guesses wrong, the good guys will lose. However, if the deputy plays a bang on himself, effectively killing himself, the sheriff may surely kill the renegade.