KWA Originals · KO Series · AEG Variable CQB · 6mmKO: RAINE-4 AEG Variable
120 rounds in a compact KO.
The KWA KO: RAINE-4 is a compact 6mm AEG airsoft rifle from KWA’s KO series, with a high-strength polymer receiver, KWA’s Variable Performance System for adjustable FPS and a gearbox that is drop-in ready for an ETU. It shoots 330–380 FPS in semi and full auto, weighs 5.1 lb, and comes with one QRF Mod 2 120-round magazine.
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What is the KO: RAINE-4?
The RAINE-4 is the compact KO with 120 rounds on board. It runs QRF Mod 2 magazines, comes with one 120-round magazine, and its KWA PDW stock keeps it short and easy to move with.
KO (KWA Originals) is KWA’s effort to reimagine how an airsoft gun should feel and look. Each KO pairs a newly developed, high-strength polymer receiver and the KO side charging handle with the same adjustable-FPS (VPS) gearbox used in the Ronin TK.45c, Ronin T6, QRF Mod series and Ronin 47. After the Eve, KWA gave the QRF Series, TK.45c and Ronin 47 the KO treatment: each is a polymer version of its metal counterpart, almost a pound lighter, and each still takes the magazines of the rifle it came from.
Who it is for: players who want a light, compact AEG for close-quarters games, with FPS they can tune for indoor and outdoor fields.
- AEG Variable Performance System, VPS tool included
- AEG 2.5+ gearbox, drop-in ready for an ETU
- High-strength polymer receiver, 5.1 lb
- Ambidextrous safety selector, magazine release and charging handle
- Switch Life Extender
- PTS flip-up sights, KWA front grip, PDW stock, Gen. 2
- K.O.R.E. 4 rail, KWA SOCOM muzzle brake
- Runs QRF Mod 2 series magazines
KO: RAINE-4 Features
AEG Variable Performance System (VPS)
Adjust FPS for indoor and outdoor games.VPS builds FPS adjustment into the gearbox. Set anywhere from 330 to 380 FPS with the included VPS tool, so one rifle can play anywhere.
Ambidextrous Controls
For every player.Built for left- and right-handed players, with an ambidextrous safety selector, magazine release and charging handle.
Ready-to-Drop-In Gearbox
Upgrade with an ETU.The gearbox is designed for drop-in upgrades with popular electronic trigger units, no modifications needed.
Switch Life Extender (SLE)
Protect your trigger switch.The KWA SLE minimizes electrical arcing, reducing wear on the trigger switch for better reliability and durability.
PTS Flip-Up Sights
Included as standard.PTS Enhanced Polymer flip-up sights come standard, so the rifle is ready to aim out of the box.
PDW Stock
Compact and adjustable.Lightweight and ergonomic, the KWA PDW stock keeps the RAINE-4 compact and easy to move with in tight spaces.
High-Strength Polymer Receiver
The newly developed KO receiver body keeps weight down.
KO Side Charging Handle
Part of every KO build.
KWA Front Grip
Listed as standard on every KO.
Adjustable Hop-Up
Tune BB flight for your BB weight and distance.
KO: RAINE-4 Specifications
| Performance | |
|---|---|
| Power system | AEG Variable (VPS), AEG 2.5+ gearbox |
| Velocity | 330–380 FPS, adjustable |
| Rate of fire | 21+ rounds per second |
| Firing modes | Safe, semi-auto, full auto |
| Magazine | QRF Mod 2, 120 rounds |
| Hop-up | Adjustable |
| Motor | KWA high torque motor |
| ETU | Drop-in ready |
| Battery | 11.1V Li-Po, T-plug (Deans) connector (not included) |
| Dimensions | |
| Length | 22 in retracted, 26.75 in extended |
| Height | 9 in |
| Outer barrel | 7.125 in |
| Inner barrel | 7.5 in |
| Weight | 5.1 lb |
| Build | |
| Platform | Compact CQB rifle |
| Receiver | High-strength polymer |
| Rail | K.O.R.E. 4 |
| Stock | PDW stock, Gen. 2 |
| Muzzle | KWA SOCOM muzzle brake (orange mock suppressor installed) |
| Sights and grip | PTS flip-up sights, KWA front grip |
| Included tools | VPS tool |
| Collection | KO Series (KWA Originals) |
Which magazines fit? See the KWA magazine compatibility chart.
What comes with the KO: RAINE-4
In the box
- KO: RAINE-4 AEG Variable
- One KWA QRF Mod 2 120-round magazine
- VPS tool
- Orange mock suppressor, installed
You will also need
- An 11.1V Li-Po battery with a T-plug (Deans) connector and a Li-Po charger (not included). The KWA 11.1V 1400mAh Li-Po is the battery KWA packs in the KO: RAINE-4 Starter Bundle.
- 6mm airsoft BBs
- Full-seal eye protection
Popular add-ons
How the KO: RAINE-4 works
Adjusting FPS with VPS
The Variable Performance System changes power at the gearbox. On the RAINE-4 you adjust it with the included VPS tool, within 330–380 FPS.
Fields set velocity limits, often lower indoors than outdoors. Set the rifle for the field you are playing and confirm it at chrono.
Which magazines to use
The RAINE-4 runs QRF Mod 2 magazines. One 120-round magazine is included, and QRF Mod 2 120-round 3-packs are sold separately.
Ready for an ETU upgrade
The gearbox is drop-in ready for popular electronic trigger units, so an upgrade needs no gearbox modification.
If you would rather start with an ETU already installed, the Ronin T6 and T10 ship with the KWA ETU.
Choosing a battery
The battery and charger are not included. This rifle takes 11.1V Li-Po batteries with a T-plug (Deans) connector.
Match the connector, check that the battery fits the stock or battery space, and charge it only with a charger made for that battery type. Ask KWA if you are not sure which size fits.
Get the KO: RAINE-4 as a bundle
New to airsoft, or buying for someone who is? The KO: RAINE-4 Starter Bundle packs the KO: RAINE-4 with a QRF Mod 2 120-round magazine 3-pack and a KWA 11.1V 1400mAh Li-Po battery.
The First Mission Bundle KO: RAINE-4 adds a KWA 140-round BB loader and KWA 0.20g Bio BBs to the same kit.
You will still need a Li-Po charger and full-seal eye protection.
Hop-up, explained
Hop-up puts backspin on the BB so it lifts and flies flatter and farther. Too little and BBs drop early. Too much and they climb.
- Start with the hop-up at its lowest setting.
- Fire a few shots at a target at your usual distance.
- Add a little hop at a time until BBs fly flat before they drop.
- Back it off if BBs start to rise. Re-check whenever you change BB weight.
Compare the KO family
Every KO shoots 330–380 FPS adjustable with VPS, runs an 11.1V T-plug Li-Po battery, has ambidextrous controls and PTS flip-up sights, and has a gearbox that is drop-in ready for an ETU. Here is how they differ.
| EVE-4 | EVE-9 | EVE-9 FDE | AVA-4 | LUCY-4 | RAINE-4 | IRIS-4 | SCARLETT-47 | |
|---|---|---|---|---|---|---|---|---|
| Magazine included | MS120 Midnight | MS120 Midnight | MS120 | QRF Mod 1 | QRF Mod 3 | QRF Mod 2 | TK.45 80-round | Ronin 47 |
| Capacity | 120 | 120 | 120 | 80 | 80 | 120 | 80 (120 compatible) | 120 |
| Rate of fire | 18.3+ rps | 18+ rps | 18+ rps | 21+ rps | 21+ rps | 21+ rps | 21+ rps | 21+ rps |
| Length | 21–26 in | 27.5–30.5 in | 27.5–30.5 in | 21.25–26 in | 21.25–26 in | 22–26.75 in | 22–26.75 in | 23.5–28.125 in |
| Outer barrel | 7 in | 10.5 in | 10.5 in | 7 in | 7 in | 7.125 in | 7 in | 8.5 in |
| Weight | 4.9 lb | 5.6 lb | 5.6 lb | 5 lb | 5 lb | 5.1 lb | 5.2 lb | 5.4 lb |
| Stock | PDW, Gen. 2 | PTS EPS | PTS EPS | PDW, Mod 1 style | PDW, Gen. 2 | PDW, Gen. 2 | PDW, Gen. 2 | PDW, Gen. 2 |
| Rail | K.O.R.E. 4 | K.O.R.E. 9 | K.O.R.E. 9 | K.O.R.E. 4 | K.O.R.E. 4 | K.O.R.E. 4 | K.O.R.E. 4 | K.O.R.E. 4 |
Lengths are retracted to extended. rps = rounds per second. Specs are from each model’s Specifications tab.
KO: RAINE-4 care and parts
- Disconnect the battery whenever you are not using the rifle.
- Charge with a charger made for your battery type (NiMH or Li-Po/Li-Fe).
- Keep the inner barrel and hop-up bucking clean if accuracy drops.
- Wipe the rifle down after each game and check screws and the rail before you play.
Find the manual and diagrams in the KWA Resources tab on this page, or in the Manuals & Diagrams library.
KO: RAINE-4 FAQ
What is the KWA KO: RAINE-4?
A 6mm AEG airsoft rifle from KWA’s KO (KWA Originals) series, with a high-strength polymer receiver, adjustable FPS (VPS) and a gearbox that is drop-in ready for an ETU. It comes with one QRF Mod 2 120-round magazine and weighs 5.1 lb.
How many FPS does the RAINE-4 shoot?
KWA lists it at 330–380 FPS, adjustable with VPS. The VPS tool is included. Set it for your field and confirm it at chrono.
Which magazines fit the RAINE-4?
QRF Mod 2 magazines. One 120-round magazine is included.
Is the RAINE-4 ambidextrous?
Yes. It has an ambidextrous safety selector, magazine release and charging handle.
Can I add an ETU?
Yes. The gearbox is drop-in ready for popular electronic trigger units, with no modifications needed.
What battery does it use?
An 11.1V Li-Po battery with a T-plug (Deans) connector. The battery and charger are not included.
Is there a starter bundle for the RAINE-4?
Yes. The RAINE-4 Starter Bundle adds a QRF Mod 2 120-round magazine 3-pack and a KWA 11.1V 1400mAh Li-Po battery. The First Mission Bundle adds the same plus a 140-round BB loader and 0.20g Bio BBs.
Can I pay for the KO: RAINE-4 AEG Variable over time?
Yes. Choose Klarna at checkout to split it into 4 interest-free payments, or Affirm to pay over time. Both are subject to approval. See Payment Options.
Do I earn KWA Rewards points on the KO: RAINE-4 AEG Variable?
Yes. KWA Rewards members earn 1 point for every $1 on orders of $50 or more, so the KO: RAINE-4 AEG Variable earns about 250 points, worth $5.00 in store credit (50 points = $1). See KWA Rewards.
Is the RAINE-4 covered by a warranty?
Every KWA gun is backed by KWA, with warranty support and in-house service in California. Protection Plus adds extended warranty coverage and a repair plan with no repair fee, discounted parts and free return shipping. See the Protection Plus page for plan details.
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