Description
Cyma M4 Keymod AEG (Nylon Fibre, MOSFET, QD Spring, with Battery and Charger, CM621)
The Cyma CM621 is a modern M4-pattern electric rifle with a slim Keymod handguard, built from tough nylon fibre polymer and fitted with a MOSFET and a quick-change spring system. This version comes with a battery and charger, so it is a complete package that is ready to play once the battery is charged.
Cyma is one of the best-known names in affordable airsoft, and the CM621 shows why: it pairs a full metal Version 2 gearbox with useful modern features normally found on more expensive guns. It is an excellent first rifle and a reliable, easy-to-maintain option for anyone who wants an M4 that works straight out of the box.
Build and materials
The receiver, handguard, pistol grip and stock are tough nylon fibre polymer, which keeps the weight low and shrugs off knocks. The outer barrel assembly, buffer tube and trim are alloy. The slim Keymod handguard is comfortable to hold, and side and lower 20mm rail adaptors let you fit a grip, torch or laser exactly where you want them. A full-length 20mm top rail on the receiver takes optics, and removable flip-up iron sights are fitted.
The six-position sliding crane stock lets you set the length of pull for your build and kit, and houses the battery. An ambidextrous sling plate is fitted.
Performance and internals
Inside is a full metal Version 2 gearbox with a MOSFET and microswitch trigger. The MOSFET protects the trigger contacts and gives a sharper trigger response, while the microswitch gives a crisp, consistent feel. The quick-change spring lets you change the main spring without splitting the gearbox, making it easy to adjust if you play at sites with different limits.
The hop-up is a gear-style adjustable unit located behind the mock bolt cover, so you can tune it to your BB weight in seconds. The outer barrel has a 14mm counter-clockwise thread under a removable birdcage flash hider, ready for a suppressor or tracer unit.
Ready to play
With the battery and charger included, there is no guesswork over battery types or connectors before your first game. Charge the battery, slide it into the stock, load the high-capacity magazine and you are ready.
Key features
- Nylon fibre polymer receiver, handguard, grip and stock
- Slim Keymod handguard with 20mm rail adaptors
- Full metal Version 2 gearbox
- MOSFET for sharper trigger response and contact protection
- Microswitch trigger
- Quick-change spring system
- Gear-style adjustable hop-up
- 14mm counter-clockwise outer barrel thread
- Removable flip-up iron sights
- Six-position crane stock housing the battery
- Battery and charger included
Compatibility
Takes standard M4/AR-15-pattern AEG magazines. The Version 2 gearbox accepts standard V2 parts, the Keymod handguard accepts Keymod rail sections and accessories, and the 14mm counter-clockwise thread suits most suppressors and tracer units. If you buy a spare battery, choose a crane-stock type and check the connector matches.
Care and maintenance
Take the battery out of the gun whenever you are not using it, and store LiPo batteries at storage charge in a fire-resistant bag. Never leave a battery charging unattended.
Use good quality, seamless 6mm BBs; cheap or damaged BBs are the most common cause of jams and can damage the hop-up rubber. Run a cleaning rod with a dry patch through the inner barrel every few games, and if a BB jams, clear it with the rod from the muzzle end with the battery removed.
After each game wipe the outside down to remove dirt and moisture, and let the gun dry at room temperature if it has been out in the rain. Turn the hop-up back off when storing it for long periods, and leave the gun on safe and on semi rather than full auto, so the spring is not left compressed.
Who is it for?
The CM621 is ideal for new players who want a complete, modern M4 package, and for experienced players looking for a light, reliable spare or loan gun. Its MOSFET and quick-change spring also make it a sensible base for upgrades.
Please note: Battery and charger are included. BBs are sold separately. Always wear suitable eye and face protection and check the rules at your site before play.
