The large whiskey bottle is a common junk item in Fallout 3 and Fallout: New Vegas.
Characteristics
Fallout 3
It's useful only as Rock-It Launcher ammunition. They can be found in every settlement and many ruins.
Fallout: New Vegas
The large wasteland tequila requires this item, making it significantly more useful. 
The player can refill this item at the Sink, creating purified water. 
Locations
Fallout 3
- 27 in Tenpenny Tower. All must be stolen.
- 10 on tables/counters at Rivet City's bar, The Muddy Rudder. Must be stolen.
- 8 in The Ninth Circle, must be stolen.
- 8 in Dukov's Place, need to be stolen.
- 2 miniature bottles in SatCom Array NN-03d-B, on a chessboard.
Fallout: New Vegas
- Large whiskey bottles can generally be found in areas with empty whiskey bottles.
- Two are found right next to the campfire near the Goodsprings source fast-travel point.
- The casino area of the Lucky 38 contains a full dozen on a set of shelves behind the bar.
- Many can be found alongside several empty whiskey bottles in the mining carts just outside of the NCR Correctional Facility main entrance.
- 11 in the Aces theater in bookcases behind the counter. Must be stolen.
- 10 in the REPCONN test site's basement and 8 in the facility.
- 9 in the Monte Carlo Suites.
- 8 on Gomorrah's main level. Must be stolen.
- There are many in one of the houses in Higgs Village in Old World Blues.
- Many Ranger stations have one near the comm officer.
- The members-only dining hall of the Ultra-Luxe has nine on a shelf in front of the door to the kitchen. They must be stolen.
Notes
- All bottles are empty and contain no alcohol.
- Large whiskey bottles share the same world model as Scotch.