CYMA Sport Gen.2 CM.508 M4 S-System AEG

CYMA
Code:
£89.99
  • 6.04mm Tightbore inner barrel
  • Gen.2 - CYMA V2 MOSFET, Deans connector
  • S-System/SIR 20mm railed handguard
CYMA Sport Gen.2 AEGs are NOT supplied with a battery or charger. We recommend using a 7.4V 1450mAh LiPo battery and a LiPo Balance Charger. A brief reminder never to leave your battery on charge unattended and always use a Battery Safe Charging Bag

If you need an affordable beginner Airsoft gun with unique looks, the CYMA CM.508 M4A1 S-System AEG is a fine choice! This battery-powered AEG is made from ABS polymer with an alloy outer barrel and an upgradable version 2 gearbox. This makes the build light and easy to move with while staying competitive on the field, ideal for younger skirmishers or those after a lightweight primary for “easy mode” fun!

The alloy version 2 gearbox features robust steel gears, a type 2 cylinder, and reinforced polymer compression parts. Also inside is a 6.04mm tightbore inner barrel and an adjustable HOP-up unit, giving you above-average accuracy. This, the “Gen.2”, features the CYMA V2 MOSFET system, preventing trigger lockups while boosting trigger response, and a quick-change spring guide for easy power tuning.

On the outside, the CM.508 is ready for 20mm Picatinny accessories such as red dot sights, scopes, flashlights, lasers and grips, ready to be customised. The barrel has 14mm CCW male threads, meaning suppressors and tracer units can be added for stealthy looks or CQB dominance. The set even includes 2 x 300 BB high-cap mags, giving you ample firepower right out of the gate. If you want to get stuck in on a limited budget, the CYMA Sport Gen.2 CM.508 M4 S-System AEG is the best option out there!

Full description

Description

CYMA Sport Gen.2 AEGs are NOT supplied with a battery or charger. We recommend using a 7.4V 1450mAh LiPo battery and a LiPo Balance Charger. A brief reminder never to leave your battery on charge unattended and always use a Battery Safe Charging Bag

Quick Start Guide

  • Charge your Battery: Place your battery inside your Battery Safe Charging Bag. Next, plug your charger into a 3-Plug UK wall socket and connect the Balance connector (small white connector) to the corresponding socket on your LiPo balance charger. Some balance chargers also require you to connect the power cable (Deans or Mini-Tamiya). Your charger will cut off when your battery reaches capacity, but you should never leave it on charge unattended.
  • Load your magazine: Open the feed hatch on the top of your High-cap magazine. Pour BBs in until full.
  • Wind your magazine: Wind the wheel on the bottom of your magazine 5-10 times or until the noise changes and the wheel becomes firm.
  • Put on your Eye Protection: Safety when using Airsoft guns should be your number 1 priority. Always wear eye protection before loading your AEG and ensure any spectators are also protected.
  • Connect your battery: Remove the lower handguard by turning the polymer screw-style locks on each side by 270 degrees (to the rear of the side rails, next to the small embossed padlock symbol). When this is done, the mock screws will lift under spring pressure and allow the lower handguard to slide forward. Inside, you'll find a male Deans battery connector. Connect this to the female Deans connector on your battery.
  • Insert your magazine: With the fire selector switch set to "SAFE" and the barrel pointed in a safe direction with your finger off the trigger, insert your magazine by pushing it up into the magazine well.
  • You're now ready to shoot! - Never shoot at animals or humans who aren't in an Airsoft skirmish

Platform Details

Starting at the front, we can see a polymer birdcage flash hider mounted to the 14mm CCW male threading at the tip of the 14.5-inch alloy outer barrel. This means the CM.508 is ready to be kitted out with a tracer unit, suppressor or alternative flash hider. If you find the pre-installed flash hider hard to remove, we recommend submerging it in warm water to loosen it and then attempting to unscrew it.

Moving along the outer barrel, we can see the military-style M4A1 barrel profile, complete with M203 grenade launcher mounting cutout. The front sight follows as we reach the handguard, constructed from polymer and replicating the real steel A.R.M.S flip-up front sight.

The sight can be deployed by lifting it and stowed again by holding down the circular button on the right side before folding it down. The presence of flip-up sights means you'll have a clearer sight picture when using a red dot sight or scope, ensuring you get a wide field of view and an unobstructed sight picture.

Following the front sight, we come to the handguard, which replicates the real steel A.R.M.S SIR, an upgraded handguard used by Green Berets and Navy SEALs during the early Global War on Terror era. The handguards are made from lightweight ABS polymer equipped with a monolithic 20mm Picatinny rail running along the top, with short rails at the 3, 6, 9 and 12 o'clock positions.

The extended top rail provides far more room on the receiver and handguard than most M4 rifles, meaning you can mount bigger scopes and even red dot sights and magnifier combos. 20mm Picatinny rails allow 20mm Picatinny accessories to be fitted wherever you need them, including vertical and angled foregrips, lasers, flashlights, and more!

Mounted to the left side of the handguard, we have our first sling point: a standard alloy footman loop compatible with a wide variety of sling types. This can be paired with the rear sling point on the sliding stock to fit a two-point rifle sling to take the burden off your arms or allow for easy transitions to a sidearm.

Moving rearward, we reach the receiver, a standard M4/AR-15 milspec design with a 3-position fire selector switch and all the details a proper replica needs. The receiver is constructed from high-density polymer with a matt black finish and features a unique serial number just above the trigger.

The fire selector switch is located on the left side, directly above the pistol grip, to provide fast and easy access for right-handed shooters. The fire selector's 90-degree throw between modes makes it quick to operate but not too easy to accidentally knock it and end up in the wrong fire mode. Each fire mode is indicated with recessed text, reading "SAFE - SEMI - AUTO", just like a real M4A1 rifle.

At the centre of the left side of the receiver, we can find the "ping pong paddle" dummy bolt release catch, which doesn't have a function in an Airsoft AEG but is included to keep the externals looking realistic. On a real AR, the bolt catch is used to close the bolt after a reload, but you don't have to do that with an AEG; simply slap a fresh mag in and get shooting!

Over on the right side of the receiver, we can see what is known as the forward assist button, located on the upper receiver behind the mock shell deflector. This button also has no function but serves to force the real M4/AR-15 bolt carrier into battery if it fails to close. The button can be pressed and is also a separate part, keeping things visually accurate to the real thing.

The magazine release is on the right side of the magazine well and is ideally positioned to be pressed with the trigger finger from a firing grip for right-handed users. Left-handed users can use their support hand thumb to press the release, and this can be done quite fast with practice.

The surface of the mag release is textured to provide the necessary gripping qualities, and is protected from accidental presses by the "magwell fence", a raised protrusion in the receiver which stops the mag release from catching on your gear as you move.

At the top rear of the receiver, you'll find the charging handle, which serves to open the dust cover and retract the mock bolt carrier, revealing the rotary HOP-up adjuster inside. The adjustable HOP-up unit allows you to adjust the amount of backspin applied to your BBs and tune for your ammo weight of choice, looking for the flattest possible trajectory.

As we reach the rear, we come to the 5-position M4/AR-15 buffer tube, offering 5 adjustment positions for the pre-installed "Colt LE" style stock. Adjusting the stock is as simple as pressing the lever on the bottom and sliding it into your position of choice, accounting for almost any body type or loadout. A sling slot for "strap" slings is present, and at the toe, we have a footman loop for cavalry-style sling setups.

Features

  • Sport Gen.2 Build - Enhanced internals, now with CYMA V2 MOSFET
  • Airsoft AEG - Powered by a rechargeable battery(not included)
  • High-density polymer build - Alloy outer barrel, agile but not flimsy
  • 6.04mm Tightbore inner barrel - Great accuracy potential
  • 14mm CCW Male threaded outer barrel - Tracer/suppressor ready
  • A.R.M.S Style folding front sight post - Flip the front sight down for a clearer view down an optic
  • 20mm Picatinny SIR/S-System quad-railed handguard - Add a vertical foregrip, flashlight or laser
  • 20mm Picatinny railed receiver - Ready for a red dot sight or scope
  • Ghost ring iron sights - Flip-up front and rear sights, rear sight is fully adjustable
  • 3 Position fire selector switch - SAFE - SEMI AUTO - FULL AUTO
  • Rotary adjustable HOP-up unit - Pull and hold back the charging handle to access
  • Realistic M4A1 receiver features - Bolt release & forward assist button realistically replicated
  • Sling points front and rear - We recommend using the front sling point & the loops on the stock
  • 5-Position M4/AR-15 Buffer tube - Adjust the stock to suit your body type and preferences
  • LE stock pre-installed - Grippy serrated butt plate, low profile design with built-in sling point
  • 2 x 300rnd High-capacity magazines included - Plenty of BBs on tap!
  • Front wired: Deans battery connector - Recommended battery: 7.4V 1450mAh LiPo
  • Version 2 gearbox:
    • Alloy shell
    • 18:1 Steel gear set
    • 8mm Steel bushings
    • Reinforced polymer piston with steel tooth
    • Reinforced polymer piston head
    • Type 2 Cylinder
    • Quick change spring system
    • 20.96mm Airseal Nozzle
    • CYMA V2 MOSFET
  • Compatible with M4/AR-15 AEG magazines - Spares are plentiful!

Suggested accessories

Package Includes

  • CYMA Sport Gen.2 CM.508 M4A1 S-System AEG

Specification

Battery Included
Battery Included
No

General

Weapon Construction External
Platform Type
Assault Rifle
Over 18 Only Icon
Over 18
Yes
Icon UKARA - United Kingdom Airsoft Retailer Association
Defence / UKARA Required
Yes, No,
Package
Included Items
Magazine x 2
Skill Level Icon
Skill Level
Beginner Player
Patrol Base - Warning Icon
Warnings
Li-Po - Never Leave Charging Unattended
Li-Po - Only Use Approved Chargers
Li-Po - Charge in a Fire Safe Area

Testing

FPS Icon
FPS, using 0.20g BBs
Approx.328fps ± 10%, using 0.20g BBs
Testing Notes
Tested using 0.20g Delta Armory EAGLE BBs

Weight and Dimension

Weight KG Icon
Weight (KG)
Approx.1.7KG
Weapon Length Collapsed
Length
77.5cm
Weapon Length Extended
Length (Extended)
85.5cm

Construction

Colour Wheel Greyscale
Primary Colour
Black
Two Tone Icon
Pre Two-Tone
No
Construction Icon
Construction
Polymer receiver, stock, buffer tube, handguard, flash hider & sights. Alloy outer barrel & internals.

Weapon Specific

Power Source Icon
Powered By
Electric
Blowback Icon
Blowback Type
None
Platform
Platform
M4 / AR-15 / M16
Magazine Style Icon
Magazine Compatibility
M4/AR-15 AEG Magazines
Fire Select Icon
Fire modes
PatrolBase | Fire Select Safe
Safe
Patrol Base | Fire Select - Semi Automatic
Semi Automatic
Patrol Base | Full Automatic
Full Automatic
Weapon Safety Features Icon
Safety Features
Trigger Lock
Shooter Configuration Icon
Shooter Configuration
Right Handed
Weapon Configuration Icon
Platform Configuration
Standard
Weapon Scale Icon
Platform Scale
1:1
Suggested BB Weight
Suggested BB Weight
0.25g

Hop-Up

Hop-Up Unit Adjuster Icon
HOP-Up Adjuster Type
Rotary
Hop-Up Unit Location Icon
HOP-Up Adjustment Location
Behind the mock bolt carrier, accessible when the charging handle is pulled and held back.

Furniture

Weapon Furniture Icon
Furniture
  • Railed Handguard
  • Railed Receiver
  • Finger Ridged Pistol Grip
  • AR Buffer Tube
  • Sliding Stock
  • Flip-Up Ironsights
  • Bird Cage Flash Hider
  • Threaded Outer Barrel
  • sling points front and rear
Rail System Icon
Rail System
20mm RIS / RAS
Icon Stock Positions
Stock Type
Sliding
Weapon Length Extended
Stock Positions
6
Sight Type Icon
Sight Type
Iron Sights
Sling Plate Icon
Sling Options
Stock, Handguard,

Barrel

Outer Barrel Length (in)
14.5''
Icon Thread Type
Outer Barrel Thread Type
Male
Icon Thread Direction
Outer Barrel Thread Direction
CCW (Counter Clockwise)
Outer Barrel Thread Size
Outer Barrel Thread Size
14mm
Inner Barrel Diameter
Inner Barrel Diameter
6.04mm
Inner Barrel Length
Inner Barrel Length
385mm

Magazine Specific

Magazine Type
Magazine Type
AEG, High Capacity,
Magazine BB Capacity
Magazine BB Capacity
Approx.300Rounds

Electric Gun Specific Information

Gearbox
Gearbox Icon
Gearbox Version
V2Gearbox
Wiring Icon
Gearbox Wiring
Front Wired
Spring Change Icon
Gearbox Quick Change Spring
Yes
Battery Specific
Battery Voltage
Battery Voltage
7.4V
Battery Type
Battery Type
Li-Po
Battery Connector
Battery Connector
Patrol Base | Icon | Deans
Deans
Suggested Battery Configuration
Suggested Battery Configuration
Block, Crane or Stick Configuration

Related video

Further Information

FAQ

Q: What Ammo/BBs do I need?

A: You'll need 6mm plastic Airsoft BBs between 0.20g and 0.28g in weight. Never attempt to shoot any form of metal ammo or "paint" ammo, as these are not designed for Airsoft AEGs and will cause internal damage.

Q: What battery do I need?

A: We recommend a 7.4V LiPo battery and a LiPo Balance charger for the CYMA Sport Gen.2 CM.508 AEG. Our recommended battery can be found here: 7.4V 1450mAh LiPo battery.

Q: How old do I need to be to buy and use an Airsoft gun?

A: Airsoft guns can be legally purchased by anyone over 18, but can be used by anyone of any age. We recommend adult supervision for users under 14 years old, at the parents' discretion. Most skirmish sites have a minimum age of 14 or over for attendees, some of which require under-18s to attend with an adult.

Q: Can I buy this for someone else?

A: Yes, provided you are over 18 and either have a Specific Defence under the VCRA, or choose a "Two-tone" colour variant.

Q: Do I need a UKARA or a License?

A: Not necessarily. You’ll need a UKARA membership or other valid defence under the VCRA to buy realistic colours (Black, Tan, etc.). Two-tone options can be purchased without UKARA. There’s no license required to own or buy Airsoft guns.

Q: Does it hurt to get shot with this?

A: It can sting, similar to a rubber band snap on bare skin, but less than a paintball. The sensation depends on distance, clothing, and protective gear. Airsoft guns produce muzzle energy around 1/14th of the average Paintball Marker, so hits hurt far less than hits from paintballs.

Q: Is an Airsoft gun dangerous?

A: Only if misused. Airsoft guns must never be brandished in public or in an area visible from public land. When transporting an Airsoft gun, ensure it is unloaded and concealed in a gun bag or case. When shooting, both the shooter and any spectators must use eye protection. It is also important that you don't shoot at targets beyond your property boundary. For more information on Airsoft Safety, check out our Airsoft Safety Guide.

Size guide

Joule Charts

Special Instructions

These table can be used as a reference to see if the BB weight you are using will be over acceptable Joulage limits at some Airsoft Sites in the UK. To check if the weight can be used chrono your weapon using the BB you intend to use, and then compare it to the chart.

FPS, Power and Joule Limits can vary from site to site, so please get in touch with where you're going to play with in advance to avoid disappointment.

Suggested limits are based on Joulage Limit rules used Halo Mill: Proving Grounds, with a 350fps limit for Automatic Replicas, 400fps for Semi-Automatic Replicas, and 500fps for Bolt Action Replicas.

Tap the tabs below to open the relevant chart for your replica.

Suggested limits are based on Joulage Limit rules used Halo Mill: Proving Grounds, and is the equivalent of 350fps, using 0.20g BB resulting in an upper limit of 1.14j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
325 0.98 1.23 1.37 1.47 1.57 1.77 1.96 2.11 2.21 2.45
328 1.00 1.25 1.40 1.50 1.60 1.80 2.00 2.15 2.25 2.50
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
335 1.04 1.30 1.46 1.56 1.67 1.88 2.09 2.24 2.35 2.61
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
345 1.11 1.38 1.55 1.66 1.77 1.99 2.21 2.38 2.49 2.76
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
355 1.17 1.46 1.64 1.76 1.87 2.11 2.34 2.52 2.63 2.93
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01

Suggested limits are based on Joulage Limit rules used at Halo Mill: Proving Grounds, and is the equivalent of 400fps, using 0.20g BB resulting in an upper limit of 1.49j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01
370 1.27 1.59 1.78 1.91 2.03 2.29 2.54 2.73 2.86 3.18
380 1.34 1.68 1.88 2.01 2.15 2.41 2.68 2.88 3.02 3.35
390 1.41 1.77 1.98 2.12 2.26 2.54 2.83 3.04 3.18 3.53
400 1.49 1.86 2.08 2.23 2.38 2.68 2.97 3.20 3.34 3.72
410 1.56 1.95 2.19 2.34 2.50 2.81 3.12 3.36 3.51 3.90

Suggested limits are based on Joulage Limit rules used at Halo Mill: Proving Grounds, and is the equivalent of 500fps, using 0.20g BB resulting in an upper limit of 2.32j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01
370 1.27 1.59 1.78 1.91 2.03 2.29 2.54 2.73 2.86 3.18
380 1.34 1.68 1.88 2.01 2.15 2.41 2.68 2.88 3.02 3.35
390 1.41 1.77 1.98 2.12 2.26 2.54 2.83 3.04 3.18 3.53
400 1.49 1.86 2.08 2.23 2.38 2.68 2.97 3.20 3.34 3.72
410 1.56 1.95 2.19 2.34 2.50 2.81 3.12 3.36 3.51 3.90
420 1.64 2.05 2.29 2.46 2.62 2.95 3.28 3.52 3.69 4.10
430 1.72 2.15 2.40 2.58 2.75 3.09 3.44 3.69 3.86 4.29
440 1.80 2.25 2.52 2.70 2.88 3.24 3.60 3.87 4.05 4.50
450 1.88 2.35 2.63 2.82 3.01 3.39 3.76 4.04 4.23 4.70
460 1.97 2.46 2.75 2.95 3.15 3.54 3.93 4.23 4.42 4.91
470 2.05 2.57 2.87 3.08 3.28 3.69 4.10 4.41 4.62 5.13
480 2.14 2.68 3.00 3.21 3.42 3.85 4.28 4.60 4.82 5.35
490 2.23 2.79 3.12 3.35 3.57 4.02 4.46 4.80 5.02 5.58
500 2.32 2.90 3.25 3.48 3.72 4.18 4.65 4.99 5.23 5.81
510 2.42 3.02 3.38 3.62 3.87 4.35 4.83 5.20 5.44 6.04

Customer reviews

5 / 5
2 reviews for CYMA Sport Gen.2 CM.508 M4 S-System AEG
Reviews.io customer reviews
Anthony Seal
Anthony Seal
Written on 29/01/2026
Very good value, robust build, excellent accuracy. Only downside is that it comes with no instructions other than basic don't shoot people. Took a little time to find the battery location, in the forestock rather than the usual location in the butt.
Rated 5 out of 5
PAUL NEED
PAUL NEED
Written on 06/10/2025
Great value and fast delivery . Thanks
Rated 5 out of 5