New Haven: Hidden House With Rider Gun:
When you obtain (do not complete) the quest "Another Piece Of The Puzzle", you can enter a blue house in New Haven. An elevator door opens up, leading to random loot, level 30 Raider Mutants, and always one of the weapons is a gun named "Rider". Its stats usually vary slightly each time you get one. The weapon is only located in this house. The weapon's "manufacturer" is "Gearbox" (the game's developer), as opposed to an in-game company such as Dahl, Hyperion, etc. Note: When this location is used with the others in New Haven for the "Unlimited guns and money" trick, it really pays off.