After the phase out of the N80 in 2051, the N99 sidearm became standard issue military gear. The N99 was known for its ability to survive in the harshest of conditions and did so in many tests, as the weapon was able to reliably be restored to working condition after an extended period of time exposed to hard elements and without maintenance.
The N99 proved to stand up to its claims and as a result, is one of the most common weapons found in use in the wasteland. While many civilian weapons were ruined beyond use in the extreme conditions following the War, the N99 is commonly able to be easily restored to working order by anyone with even the most basic knowledge of firearm mechanics.
However, an N99 in poor condition can often deliver low target and armor penetration, frequent jamming, and greatly reduced accuracy. Fortunately, the weapon was produced in great numbers and many units are available for replacement parts.
An N99 10mm pistol equipped with a suppressor. The benefit of the suppressor is that when the player fires at an enemy and kills them with the first shot, no nearby enemies will be alerted. The downside is the slightly decreased damage compared to a regular 10mm pistol. If you do not kill your target in the first few shots, they will likely alert nearby enemies.
It is a great weapon for stealthy characters, as a good Sneak and Small Guns skill will give you an advantage while using this weapon. It counts as a silent weapon for sneaking purposes, and shooting it will not increase your chances of being detected. Also, if you have a high enough Small Guns skill, the silenced 10mm pistol makes a good close-quarter weapon in locations such as the Bethesda Ruins, the Museum of History, and other office building type settings. It's a handy weapon to carry, as it weighs only 3 pounds and is ideal for snuffing out weaker enemies like radroaches, mole rats, and sometimes even raiders without alerting other (stronger) enemies.
Sim version Operation: Anchorage (add-on) - A sim-only version of the weapon which has been re-skinned to appear newer and less worn. It also differs in health, with a whopping 999,150 hit points, essentially preventing the gun from ever degrading, This weapon is not normally accessible outside of the simulation.
The following is based on Fallout 3 cut content and has not been confirmed by canon sources.
10mm alloy steel pistol - Another version of the weapon was cut from the Operation Anchorage add-on, it differs from the standard 10mm pistol in appearance only, using the same new skin as the sim only version.
Sonora Cruz' 10mm pistol - a unique pistol on Sonora Cruz. It deals a whopping 100 damage, but Sonora always flees from enemies and never uses her pistol.
End of information based on Fallout 3 cut content.
In the caves under Oasis, after you decide the fate of Harold, head to the door to your right, there is a cave where you can find it. You cannot go back, but you can dive into the nearby water and exit via the underwater door back to Oasis.
Underwater by a sunken car at the docks near Arefu.
Operation: Anchorage (add-on) A pre-war varient will be given to player at the beginning of the Anchorage Reclamation simulation, and will be removed after you take out the Chinese Artilleries.