The Hairpin has always been ARC Raiders’ quiet pistol. It is common, silenced, and slowed down by a slide you have to work between every shot. The Frozen Trail update’s weapon amplification system changes that. Amplified, the Hairpin gets a fifth level and a small upgrade tree. One branch turns it into a semi-automatic pistol that can tear plates off a Vaporizer and blow out a Bastion’s knee.
Quick answer: Yes, with the Semi-Auto amplification. It adds 150 percent fire rate, which lets the Hairpin break ARC weak points such as Bastion knee joints, even though its ARC armor penetration stays Very Weak.
What the Amplified Hairpin is
The base Hairpin is a common pistol that fires Light Ammo from an 8-round magazine. It has one mod slot, which takes the Extended Light Mag line, and four upgrade levels, I through IV. Its built-in silencer gives it a Stealth rating of 70. The trade-off is the slide action, which makes follow-up shots slow.
Hairpin IV is followed by Amplifying. Since the Hairpin is a common weapon, this process requires an Amplification Module Mk. I and a level 4 Gunsmith, while the Research Station must also be level 4. Modules are available during the ARC Frigate event and inside the fallen Emperor at Pendola Pass. Amplifying automatically adds Amplified Durability, increasing the weapon’s maximum durability to 200. The upgraded pistol weighs 3, just like the base version.
Amplification gives the gun a new model and opens a tree of upgrade nodes. Each node you activate is permanent. You can’t remove it or swap it later.
Amplified Hairpin upgrade tree: Three paths, one choice
Amplified Durability branches into Incendiary Rounds, Semi-Auto, and Tracker Rounds. These three exclude each other, so picking one locks out the other two for good. Only Semi-Auto has a follow-up node, Sprint Shooting.
| Node | Effect | Requires | Can’t combine with |
|---|---|---|---|
| Tracker Rounds | +5s tracking on hit | Amplified Durability | Incendiary Rounds, Semi-Auto |
| Incendiary Rounds | +5/s burn, +2s duration | Amplified Durability | Semi-Auto, Tracker Rounds |
| Semi-Auto | +150% fire rate | Amplified Durability | Incendiary Rounds, Tracker Rounds |
| Sprint Shooting | Fire while sprinting | Semi-Auto | None listed |
Tracker Rounds swap the Hairpin’s bullets for rounds that briefly reveal whatever they hit. That is a scouting tool, not a damage upgrade. Incendiary Rounds add 10 burn damage per hit, 5 per second over two seconds. That is small next to a 20-damage bullet that already has slow follow-up shots. Semi-Auto removes the manual slide cycle, and that change matters more than the other two.
Each node also needs research and materials. Here is what each path calls for:
- Tracker Rounds: one Matriarch Reactor.
- Incendiary Rounds: Fossilized Lightning, plus the Thermite-Tipped Rounds research.
- Semi-Auto: the Trigger Reset Systems research.
- Sprint Shooting: the Mobile-Fire Grip Fittings research.
- Semi-Auto and Sprint Shooting together: three Fluted Rotor Cores and three Pneumatic Actuators.
Semi-Auto Hairpin stats and time to kill
Semi-Auto isn’t free. Alongside the 150 percent fire rate increase, it cuts the headshot damage multiplier by 20 percent and raises per-shot dispersion by 40 percent. With Semi-Auto installed, the stat card reads Damage 20, Fire Rate 12.5, Range 36, Stability 72.9, Agility 84.3, and Stealth 70. The silencer survives the conversion, and the Hairpin IV bonuses of 30 percent faster fire rate and 40 percent faster reloads carry over.
Your raw rate of fire changes most. Against raiders, the per-shot damage and shot count stay the same, so the gain shows up as time. Here are the time-to-kill figures for body shots at 10 meters with every shot landing:
| Target shield | Shots | Slide-action | Semi-Auto |
|---|---|---|---|
| No shield | 5 | 3.5s | 1.4s |
| Light | 6 | 4.4s | 1.7s |
| Medium | 7 | 5.2s | 2.1s |
| Heavy | 7 | 5.2s | 2.1s |
Damage holds at full strength out to 130 meters and falls to 60 percent from 150 meters. Under 5 meters, you get 20 percent bonus damage. That close-range bonus helps explain a five-shot down on a shielded raider in a friendly PvP test.
Sprint Shooting lets you keep firing at full sprint and through a dive, so you can reposition without dropping your aim. It only exists on the Semi-Auto branch, so it’s the default second pick for anyone who takes Semi-Auto.
Amplified Hairpin vs. ARC: Weak points, not armor
The Hairpin’s ARC Armor Penetration rating is Very Weak, and no Hairpin node changes that. Unlike the Kettle’s X-Rounds path, the Hairpin tree has no anti-armor option. So it can’t punch through ARC plating. It wins by putting many shots on exposed weak points quickly.
The footage takes place on Riven Tides, a map rated 5 of 5 for difficulty, and the results line up with that. Hits on thrusters and unarmored vents land for around 60 damage. Wasps and Thrusters go down in two to six shots, and Hornets and Fireflies fall in quick succession.
Larger machines take more time but follow the same pattern. A Vaporizer goes down to sustained fire both indoors and outdoors, losing its armor plates before the pistol finishes it. Against a Bastion, shots on the knee joint land for 30 to 70 damage each, and steady fire blows the leg off entirely. The Bastion’s leg comes off because the Hairpin keeps hitting one weak point quickly, not because it pierces armor.
Amplified Hairpin durability and repair costs
Shooting faster also wears the gun out faster. One raid of roughly 300 to 400 rounds took an Amplified Hairpin from 200 durability down to 17. Amplified weapons can’t be repaired with ordinary parts. Repairs take Amplified Fragments, and each node you add raises the cost.
| Configuration | Repair cost | Durability restored |
|---|---|---|
| Amplified, no nodes | 7 Amplified Fragments | 50% |
| Semi-Auto | 17 Amplified Fragments | 50% |
| Semi-Auto + Sprint Shooting | 27 Amplified Fragments | 160, with a +30% Repair Boost |
Repair boosts from expeditions are percentage-based, so they go further on amplified weapons. Recycling an Amplification Module Mk. I returns 7 Amplified Fragments.
A knocked-out raider drops an amplified weapon at 10 percent durability, so a looted Amplified Hairpin usually needs a repair before it’s worth carrying.
Hairpin amplification nodes on other amplified weapons
All four Hairpin node names also appear on other amplified weapons. Here is where each one shows up, with the weapon’s category and item weight:
| Node | Also on | Category | Weight |
|---|---|---|---|
| Semi-Auto |  Amplified Bettina | Assault Rifle | 11 |
| Sprint Shooting |  Amplified Burletta | Pistol | 4 |
| Sprint Shooting |  Amplified Canto | SMG | 4 |
| Sprint Shooting |  Amplified Rascal | Special | 4 |
| Incendiary Rounds |  Amplified Aphelion | Battle Rifle | 10 |
| Incendiary Rounds | Amplified Canto | SMG | 4 |
| Incendiary Rounds |  Amplified Rattler | Assault Rifle | 6 |
| Tracker Rounds |  Amplified Osprey | Sniper Rifle | 7 |
A shared name doesn’t mean shared numbers. On the Bettina, Semi-Auto cuts fire rate by 20 percent in exchange for extra base damage and tighter spread, which is close to the reverse of what it does on the Hairpin. The Burletta is the only other amplified pistol. It weighs 4 to the Hairpin’s 3 and reaches Sprint Shooting through its own Burst Fire and Full-Auto branches rather than Semi-Auto. For a common pistol that started as a stealth tool, the Semi-Auto Hairpin now takes down flying ARC quickly and can cripple heavy ARC through their weak points. The cost is a steady supply of Amplified Fragments.
