It's Always Sunny in Philadelphia - Season 01 - Episode 05 - Gun Control

Upon learning that the bar's safe has been stolen, the guys take matters into their own hands and buy a gun. Shortly thereafter gun fever strikes, bringing out the inner-Hardy Boy in Dennis and Mac, who vow to catch the thief, and the inner-tough guy in Charlie, who uses the gun to intimidate his nagging landlord. Meanwhile, gun fever also hits Dee, as she feigns interest in guns to try and seal the deal with Colin, a crush that only seems to have mild interest in her.