Sentinel Firing Cores are one of the most restrictive bottlenecks in Arc Raiders. You need four of them to upgrade the Gunsmith workbench from level 2 to level 3, and they only come from a handful of rare Arc spawns and containers.
The item itself is a rare, recyclable Arc component. It drops primarily from Sentinel sniper turrets and can also appear as loot in certain Arc containers such as ARC Couriers. Once collected and extracted, each Sentinel Firing Core can be recycled into Mechanical Components and ARC Alloy, or spent directly on the Gunsmith upgrade.
What Sentinel Firing Cores are used for
| Use | Details |
|---|---|
| Workbench upgrade | Required to upgrade the Gunsmith workbench from Gunsmith 2 to Gunsmith 3 (four Sentinel Firing Cores needed, plus other materials). |
| Recycling | Can be recycled into Mechanical Components and ARC Alloy. |
| Salvaging | Salvaging returns a smaller amount of Mechanical Components. |
| Trade value | Counts as a rare Arc loot item with a relatively high sell price compared with common materials. |
Because Gunsmith 3 unlocks higher-tier weapons and mods, most players will want at least four Sentinel Firing Cores as early as possible rather than recycling or selling them.
How Sentinel Firing Cores drop
There are two reliable sources for Sentinel Firing Cores:
| Source | How it works | Notes |
|---|---|---|
| Sentinels | Ceiling or tower-mounted sniper turrets. Destroy the turret, then loot the fallen chassis to obtain a chance at a Sentinel Firing Core. | Spawn on fixed points on every map, but only in some matches and only at one of several potential spots. |
| ARC Courier | Large, crashed Arc containers that can be breached. They can roll Sentinel parts as loot, including Sentinel Firing Cores. | Appear across all maps, with many possible spawn points around Arc-heavy areas. |
Sentinel turrets are easy to confuse with regular defensive turrets. The ones you need are the long-range “laser” snipers attached high on buildings, ceilings, or towers, with a very narrow red beam and long sightlines.
Once a Sentinel dies, it drops its hull piece, usually all the way down to the ground below its mounting point. You must physically loot this wreck to have any chance of getting a Sentinel Firing Core. If another Raider gets there first, or the wreck clips into the environment, you will not get the item.
Best Sentinel Firing Core farm on Dam Battlegrounds
Dam Battlegrounds has the most consistent Sentinel activity and is the best map to focus on if you only care about finishing the Gunsmith 3 requirement.
| Area (Dam Battlegrounds) | Sentinel behavior | Notes |
|---|---|---|
| Research & Development / Administration – blue exterior staircase | Frequent Sentinel spawn mounted high on the corner of the building overlooking the staircase. | Most reliable Sentinel spot in the game. Very contested; expect other Raiders to race you there. |
| Destroyed dam – side near Control Tower | Possible Sentinel spawn overlooking The Breach side of the broken dam. | Much rarer than the R&D spawn; may appear only occasionally over many runs. |
| Destroyed dam – side near Power Generation Complex / Pipeline Tower | Another potential tower or structure mount at the opposite end of the dam. | Also rare; treat it as a bonus check while rotating between spots. |
A practical loop looks like this:
- Drop into Dam Battlegrounds with a light or free loadout so you can reset quickly.
- Sprint directly to the Research & Development building and check the blue exterior staircase corner for the Sentinel.
- If the turret is present, use the building and stairs as cover to strafe, peek, and destroy it, then immediately run down to the base of the building to loot the chassis.
- If it is not present or already destroyed, cut across to the dam and quickly scan both ends for another Sentinel spawn before deciding whether to continue the match or withdraw and requeue.
Other Sentinel locations on Buried City, Spaceport, and Blue Gate
Sentinels can appear on all four main maps. They are far less predictable than on Dam, but they are still worth watching for while you are already on an expedition.
| Map | Location | Description of Sentinel spot |
|---|---|---|
| Buried City | Townhall bell tower | A Sentinel can perch in the yellow tower structure above the Townhall in the central plaza, firing down over the square. |
| Buried City | Santa Maria Houses courtyard | Another reported Sentinel spawn inside the courtyard you visit for the Digging Up Dirt quest. |
| Spaceport | Rocket Assembly | Potential high-mounted turret overlooking the rocket assembly area. |
| Spaceport | Container Storage | Possible spawn above or between stacked containers, watching the lanes. |
| Spaceport | Control Tower A6 | Reported Sentinel spawn attached high on or near the control tower structure. |
| Blue Gate | Checkpoint (northeast concrete area) | Sentinel can appear on concrete structures around the main checkpoint in the center of the map. |
| Blue Gate | Pilgrim's Peak tower / antenna | Another possible spawn on a tall tower or antenna toward the north or northeast edge of the map. |
Spawn rates on these maps are low. You might not see a Sentinel on Buried City, Spaceport, or Blue Gate for multiple expeditions in a row. Treat these as opportunistic kills: if you happen to be passing through these areas, look up and scan for the familiar laser beam or turret silhouette, but do not rely on them as your main farm.
Using ARC Couriers to get Sentinel Firing Cores
ARC Couriers are crashed Arc vessels scattered across every map, emitting smoke and acting as breachable loot containers. They use the same “breach and loot” interaction as other Arc objects but have a small chance to drop parts from several Arc enemy types, including Sentinel Firing Cores.
| Container | How to recognize | Why it matters |
|---|---|---|
| ARC Courier | Large, crashed Arc structure with smoke, not the long, cigarette-shaped probes. | Can drop Sentinel Firing Cores among other Arc machine parts, giving you cores without winning turret races. |
ARC Couriers can appear on all four maps, with many possible spawn locations. Dam Battlegrounds is particularly dense with Courier spawns around the Research & Development building and nearby roads, which lines up well with the main Sentinel turret route.
For a more relaxed route that does not revolve around winning PvP races to a single turret spawn, you can:
- Queue into any map where you are comfortable surviving.
- Prioritize traveling through Arc-heavy areas where Couriers, probes, and other Arc structures tend to crash.
- Breach every ARC Courier you encounter and loot the container fully before moving on.
Progress through Couriers alone is slower and streakier, but it avoids the frustration of finding every Sentinel already destroyed.
How to safely destroy and loot Sentinel turrets
Sentinels are long-range sniper turrets with high damage, especially if you are caught in the open. They are also heavily armored from the front.
| Aspect | Recommendation |
|---|---|
| Loadout safety | Use an augment that grants Safe Pockets so any Sentinel Firing Core you collect is protected even if you die before extraction. |
| Weapons | Bring a high-damage primary (rifle, heavy weapon, or strong shotgun for close angles) and at least one explosive such as a grenade to speed up turret kills. |
| Approach | Use nearby walls, staircases, towers, and debris as cover. Peek to bait shots, then quickly lean out to return fire while the turret recovers. |
| Positioning | Whenever possible, attack from the side or at an upward angle that exposes its weak points instead of shooting straight into its armored face. |
| Post-kill loot | Mark where the turret is mounted, then immediately check the likely fall zone underneath and around that structure for the dropped hull. |
On Buried City in particular, Sentinels in the Townhall tower tend to drop their wreckage down into the sand below, often within aggro range of a large Arc patrol. Be ready to either clear the area first or quickly dash in, loot, and retreat.
Minimizing frustration while farming Sentinel Firing Cores
Because the spawn logic is stingy and other Raiders are competing for the same drop, Sentinel Firing Cores feel scarcer than their raw drop rate suggests. A few patterns make the grind more bearable:
- Commit to short, targeted runs. For pure core farming, focus on Dam Battlegrounds, sprint to the R&D staircase, check the dam ends, and extract or withdraw if nothing is there.
- Layer the farm into normal play. While running quests or looting general materials on any map, always detour briefly through known Sentinel spots and breach every ARC Courier.
- Use Safe Pockets when you care about the item. Gunsmith 3 is a big upgrade; protecting each core with a Safe Pocket slot is worth more than an extra grenade or trinket.
- Expect dry streaks. Sentinels do not spawn every match, and even when they do, the core itself is not guaranteed. Thinking in terms of “runs per core” instead of “match by match” helps keep expectations realistic.
Once you secure four Sentinel Firing Cores and extract with them, upgrade the Gunsmith at your workshop, then store any extras in your stash. From that point, Sentinel Firing Cores become more of a nice recycling bonus than a hard progression gate.
