KWA KM4A1 AEG
The classic full-length KWA carbine
The KWA KM4A1 is a full-length 6mm AEG airsoft carbine on KWA’s AEG 2 gearbox, built to run on Li-Po batteries. It shoots 385–410 FPS in semi and full auto, comes with one K120 120-round magazine, and has a 14.5-inch outer barrel, a two-piece clamshell handguard, an A2 birdcage and a KWA Crane stock.
Looking for one today?
The KM4A1 is out of stock right now. These KWA models are the closest match today.
KWA Rewards
Earn 249 points on this item, worth $4.98 in store credit. New members get 100 points for signing up and 500 bonus points on their first order.
How KWA Rewards worksPay over time
Split it into 4 interest-free payments of $62.49 with Klarna, or pay over time with Affirm. Choose either at checkout.
See payment optionsFree shipping
This item ships free, since orders over $200 ship free in the contiguous US.
Shipping detailsKlarna and Affirm are subject to approval. See payment terms. A higher initial payment may be required for some consumers. CA resident loans made or arranged pursuant to a California Financing Law license.
What is the KM4A1?
The KM4A1 is KWA’s classic M4A1-style carbine. KWA built it to handle the extra power of Li-Po batteries, with a reinforced metal gearbox, a combination of 8 mm and 9 mm ball bearing bushings, and case-hardened precision metal gears.
Heavy-duty springs are matched to a high torque motor, and the upper and lower receivers are made from high-grade metal alloy.
- AEG 2 gearbox, electronic trigger ready
- Reinforced metal gearbox with 8 mm and 9 mm ball bearing bushings
- Case-hardened precision metal gears
- KWA high torque motor and heavy-duty springs
- Metal alloy upper and lower receivers
- Two-piece clamshell handguard and A2 birdcage
- KWA Crane stock
- Takes K120 and MS120 magazines
KM4A1 Features
Li-Po Ready
Built to handle the extra power of Li-Po batteries.
Metal Gearbox
8 mm and 9 mm bearings with case-hardened gears.
Full-Length Barrel
14.5-inch outer barrel, 385–410 FPS.
KM4A1 Specifications
| Performance | |
|---|---|
| Power system | AEG 2 gearbox |
| Velocity | 385–410 FPS |
| Rate of fire | 13.1+ rounds per second |
| Firing modes | Safe, semi-auto, full auto |
| Magazine | K120 included, 120 rounds. MS120 compatible |
| Hop-up | Adjustable |
| Motor | KWA high torque motor |
| Electronic trigger | Ready |
| Battery | NiMH or Li-Po/Li-Fe, Tamiya connector (2020 version) (not included) |
| Dimensions | |
| Length | 31.75 in retracted, 35 in extended |
| Outer barrel | 14.5 in |
| Inner barrel | 15.55 in |
| Weight | 7.21 lb |
| Build | |
| Platform | Carbine |
| Rail | Two-piece clamshell handguard |
| Stock | KWA Crane stock |
| Muzzle | A2 birdcage |
| Body | Full metal alloy |
Which magazines fit? See the KWA magazine compatibility chart.
What comes with the KM4A1
How the KM4A1 works
Which magazines to use
The KM4A1 comes with one KWA K120 120-round mid-cap. Spare K120s come in 6-packs, and KWA also lists the MS120 as compatible. For a bigger load, the K400 holds 400 rounds.
Ready for an electronic trigger
KWA lists the AEG 2 gearbox in this rifle as electronic trigger ready, so it can take an electronic trigger unit as an upgrade.
If you would rather start with an ETU already installed, the Ronin T6 and Ronin T10 ship with the KWA ETU.
Choosing a battery
The battery and charger are not included. This rifle takes NiMH or Li-Po/Li-Fe batteries with a Tamiya connector (2020 version).
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.
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.
KM4 SR7 vs KM4 CQB vs KM4A1
All three are full metal AEG 2 rifles with a KWA Crane stock, an A2 birdcage, adjustable hop-up and an electronic-trigger-ready gearbox.
| KM4 SR7 | KM4 CQB | KM4A1 | |
|---|---|---|---|
| Velocity | 340–360 FPS | 340–360 FPS | 385–410 FPS |
| Rate of fire | 14+ rounds per second | 13.9+ rounds per second | 13.1+ rounds per second |
| Outer barrel | 10.75 in | 10.5 in | 14.5 in |
| Inner barrel | 10.75 in | 10.75 in | 15.55 in |
| Length | 28–31.25 in | 27.75–31 in | 31.75–35 in |
| Weight | 6.79 lb | 6.70 lb | 7.21 lb |
| Handguard | 6.13-inch Picatinny rail | Two-piece clamshell handguard | Two-piece clamshell handguard |
| Battery connector | Tamiya (2020 version) | Deans / T-plug (2022 version) | Tamiya (2020 version) |
| Platform | SBR | Carbine | Carbine |
KM4A1 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 manuals and exploded diagrams in the KWA Resources tab on this page, or in the Manuals & Diagrams library.
KM4A1 FAQ
What is the KWA KM4A1?
A full-length 6mm AEG airsoft carbine from KWA with the AEG 2 gearbox, a 14.5-inch outer barrel, a clamshell handguard and a KWA Crane stock.
Is the KM4A1 in stock?
Not right now. The block near the top of this page shows current KWA alternatives.
How many FPS does the KM4A1 shoot?
KWA lists it at 385–410 FPS.
Which magazines fit the KM4A1?
It comes with one KWA K120 120-round magazine, and KWA lists the MS120 as compatible.
Can I add an electronic trigger?
KWA lists the KM4A1 gearbox as electronic trigger ready.
Is a battery included?
No. The battery and charger are sold separately. It takes NiMH or Li-Po/Li-Fe batteries with a Tamiya connector (2020 version).
Can I pay for the KM4A1 AEG 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 KM4A1 AEG?
Yes. KWA Rewards members earn 1 point for every $1 on orders of $50 or more, so the KM4A1 AEG earns about 249 points, worth $4.98 in store credit (50 points = $1). See KWA Rewards.
Is the KM4A1 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.
