Is the CAA M4 S1 AEG Sport Series Carbine Any Good?

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Is the CAA M4 S1 AEG Sport Series Carbine Any Good
Category: Product Guides

One of the biggest questions we get asked is ‘is XYZ airsoft guns any good?’, and rightly so – our customers want to make sure they’re getting the best bang for their buck. With that in mind, over the next few months we’re going to be taking a look at some of the most popular searches on our website and asking the question – is it any good?


The M4 Carbine is a 5.56×45mm NATO, air-cooled, gas-operated, direct impingement, magazine-fed, select-fire carbine. It has a 14.5 in (370 mm) barrel and a telescoping stock. It is essentially a lighter and shorter variant of the M16A2 assault rifle.

The M4 is extensively used by the United States Armed Forces and is largely replacing the M16 rifle in United States Army and United States Marine Corps (USMC) combat units as the primary infantry weapon and service rifle. The M4 has been adopted by over 60 countries worldwide, and has been described as “one of the defining firearms of the 21st century”.

Since its adoption in 1994, the M4 has undergone over 90 modifications to improve the weapon’s ergonomics and modularity, including the M4A1, which strengthened the barrel and removed the burst-fire option, and the SOPMOD, an accessory kit containing optical attachments.


Founded in 2004, CAA is a long-established designer, developer and world class producer of modern tactical accessories, optics, tools and upgrades targeting the Armed Forces, Law Enforcement and firearm enthusiasts across the globe.

CAA is proud to have invented many modern tactical accessories that have become the benchmark for the firearm industry.

CAA outfits firearms for maximum performance in any environment. Their innovative products improve your accuracy, grip, aim, and enhance balance and performance. When equipping your firearm with their range of accessories, the user’s daily operations will become fluid and consistent.


So it’s that all-important time once more… the time we give you a little breakdown and our honest thoughts on the item.

The CAA M4S1 is equipped with a nylon fiber outer barrel, and a lightweight nylon fibre M4S1 Picatinny Rail System. The official CAA trademarks are laser engraved on the nylon fibre receiver. The ergonomic designed nylon fibre pistol grip provides great comfort.

The nylon fibre collapsible buttstock can be set to 6 different positions. There is a storage compartment in the stock for 4 x CR123 batteries. The rubber non-slip buttpad with a tapered angle allows faster shouldering and increase comfort with body armour. The side rail on the buttstock can be used to install an Adjustable Cheek-rest, magazine pouch or shell holder. A QD sling swivel can be attached to 6 different positions on the stock and handguard.

The outer barrel is in part metal, but its end compensator is again made from plastic. It is worth mentioning the three holes on each side of the weapon which is used to clip onto QD mounts on the sling.

Internally though, the CAA M4S1 used to be a bit of a mess, until King Arms got involved. The CAA M4S1 runs a number of King Arms internals, with the metal-reinforced gearbox contains high-quality steel gears, precision ball bearings 7 mm, a spring M120, reinforced cylinder head and a vacuum piston head.

Honestly, without the King Arms upgrades, we would likely be placing the CAA M4S1 firmly in the “It is definitely not any good” category. While the CAA M4S1 looks the part, the non-King Arms variants simply underperformed. However, when you combine the manufacturing capabilities of CAA with the airsoft knowledge gathered by King Arms over the years, you honestly have a brilliant AEG that will most certainly give you £150 worth of fun!

Take a closer look at the CAA M4S1 AEG Sport Series Carbine


We supply quality airsoft guns for fun and skirmishing – on our website you will find something for everyone. If you’re a beginner we’ll make sure you walk away with the perfect starter kit. We recommend that you take a look at our exclusive range of airsoft guns and accessories. Airsoft guns and pistols can be purchased by anyone over the age of 18 plus we offer fast low-cost delivery to your door. Don’t be fooled by copycat websites, JBBG has been around since 2009! If you need any further product information please go get in touch via the Contact Us page on this website.

You can see our full range of airsoft guns, airsoft rifles or airsoft pistols on the Just BB Guns category product pages. We also have a large number of BBs and airsoft accessories all at great low prices.

Just BB Guns: Trimex House, Pier Road, Feltham, TW14 0TW
Call us now: 0330 900 5224
E-mail Address: [email protected]

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