A Pair of Dead Desperados, II

A Pair of Dead Desperados, II is an unmarked quest in Fallout: New Vegas.

Detailed walkthrough
Talking to Sammy and Pauline Wins at their shack near Westside reveals they looted the Vikki and Vance Casino back in Primm. They will tell the Courier of their ambitious plan to rob all the casinos on the Strip, and the player can either tell them that's the worst plan they've ever heard, or pass a Speech check of 55 to tell them that the player thinks that the plan is great. Doing this will cause Sammy to give you the combination to the safe containing Vance's 9mm submachine gun.

Alternatively, the courier can simply gun them down for some unique hats.

After the courier has aquired the 9mm Machine Gun, he can return it to Primm Slim for 1500 caps. The gun will not be placed back into the case, and you can't find it on Slim if you gun him down. Therefore, the only way to re-aquire it is to spawn it through the Gamebryo engine.

Behind the scenes

 * The code to the safe Sammy Wins gives you, 05-23-34, is a reference to the date the real Bonnie and Clyde were shot in Louisiana.