|Dropped by||Informant Event|
Not to be confused with Charged Chamber.
Primed Chamber gives the first shot you fire from a fresh clip a damage bonus.
- This was originally distributed to the top 100 ranked players in the Informant Event, based on the number of Informer kills.
- For a short time after Update 10.6 it could have been acquired via transmutation. This was due to a bug where all mods (including unreleased ones) became obtainable through transmutation. This has since been fixed, but players who obtained the mod this way were allowed to keep them.
- During Livestream 17 and 18, one lucky winner was given a Primed Chamber mod through random selection. It is unknown if they will continue giving away Primed Chamber this way.
DERebecca has stated the following on the topic of people being upset over Primed Chamber being exclusive: "Ah, we did not say the Primed Chamber mod is Exclusive to the Drone weekend event, it was just the first time it was introduced. Sorry for the confusion there! I imagine it will appear again in future events." 
Due to the release of Charged Chamber it seems unlikely that Primed Chamber will be released as a drop however the possibility of Primed Chamber appearing in another event has been confirmed in livestream 17. DE said they were going to have it as a Gradivus Dilemma reward, but 'didn't get that far' and are looking for the next appropriate event to add it to.
- Mod confirmed to only work with Sniper Rifles and not with bows such as the Dread, Paris or Paris Prime.
- Stacks additively with its weaker counterpart, Charged Chamber for up to 140% bonus damage.
- Works very well with the Vectis, as each shot is considered the first shot in the clip.