Airsoft Basics: What is an M4?
What is an M4?
This question is harder to answer than you might think! In Airsoft terms, an M4 is a replica Airsoft rifle which shoots 6mm BBs at Airsoft skirmish safe velocities using compressed air or gas, and is based on the shape and external design of a real world M4A1 or AR15 rifle.
Airsoft M4s are available in a multitude of different lengths and shapes with different operating systems and features, and are one of the best Airsoft platforms to start the sport with thanks to the availability of accessories, simple and intuitive controls and tried and tested internals.
The term "Airsoft M4" is a very general term which simply describes the external shape of the Airsoft gun, and with the plethora of M4 rifles available for Airsoft it is very important that you choose the right kind of M4 for your needs. With this in mind, lets get stuck in and give you a brief overview of the different types of Airsoft M4 out there, and what type of skirmisher they suit the most!
M4 Assault Rifle Types
What type of M4 suits your playstyle? We can't tell you, but what we can do is give you the low down on the different M4 Assault rifle types and what they do best!
M4 AEGs
The M4 AEG is the Airsoft platform we always recommend to new players, and is by far the most common type of Airsoft gun, and M4, you will see on skirmish sites today.
AEGs are the perfect tool for a new player to start the sport, and are also commonly used by veteran Airsofters for their wide availability of parts and magazines, their wealth of customisation opportunities and the fact that they look pretty darned awesome however they are dressed up!
AEGs use a gearbox to pull the internal piston back and compress the spring via a powerful electric motor, using a rechargeable battery as a power source. Being powered by a battery means AEGs can fire as fast as you can pull the trigger, with no need to cock the rifle before each shot.
For performance in-game, AEGs are hard to beat, and this is the main reason they still form the bedrock of Airsoft as a sport. AEGs just work, require comparatively little maintenance and are realistic and exciting to operate without overwhelming newer players with advanced features they may see little advantage in using.
Practically all M4 AEGs come with an adjustable HOP-up, allowing you to extend your range and tune your gun for different ammo weights, and a 3-position fire selector providing safe, semi-automatic and fully automatic fire modes. If you are just getting started and you like the looks of the M4, an AEG will see you well equipped to start your Airsoft adventure.
M4 GBBR
GBBR stands for Gas Blow-Back Rifle, and GBBRs are considered a great choice for advanced Airsofters who are looking for more of a challenge, both in-game and in the technical aspects.
Like M4 AEGs, M4 GBBRs follow the external shape of the real M4 rifle. GBBRs differ in that they go as far as to almost perfectly match the dimensions of the real thing, and have a totally different feel, balance and operating procedure than the electricity-powered AEG M4s.
The prime feature of GBBRs is their realistic functionality and the immersive recoil they provide when fired. The incredibly realistic bolt carrier cycles back, providing a realistic "clank clank clank" sound and shooting a dramatic cloud of excess gas out of the ejection port with each shot.
Shooting a GBBR is an awesome experience, and as close as you can get to shooting a real M4, but as with all aspects of Airsofting, there are balancing factors.
Using a GBBR is far more effort than an AEG, and when it comes to performance, a skilled skirmisher will have to work very hard to keep up with an M4 AEG user in game, though the GBBR emphasises a different aspect of the sport, and is a popular choice for different reasons.
M4 GBBRs are an almost perfect simulation of the real M4. You need to pull the charging handle back to load the first BB, and at the end of a magazine, the GBBR's bolt carrier will lock back. When you load a fresh magazine you need to pull the charging handle, or hit the bolt release catch before firing again. This is exactly how the real M4 operates and is a big reason for GBBRs being so popular in the Milsim scene.
Due to the gas reservoir located inside the GBBR magazine, GBBRs are generally restricted to 30-50 round magazines, meaning you will need a whole lot of them to have as much firepower as an M4 AEG user with a single high-cap magazine.
For Milsim skirmishes a GBBR is the best thing to give you the feel of using a real steel M4 without actually having to exchange lead with a real enemy force. Their low capacity magazines lend themselves well to this role, and if you are the type to value having a realistic experience over getting the most kills, a GBBR would suit you well, though we always advise starting with an AEG if you are fresh to the sport, and moving up to a GBBR when you decide you want a challenge!
Other M4 Airsoft Rifles
Being so prolific and popular, the M4 is also available in several more specialised setups. These M4s have proprietary internals and are generally not the best choice for beginners, but offer some impressive features for a player who wants a bit more from their M4.
Tokyo Marui NGRS M4s
Designed as the next evolution of the AEG platform, the Tokyo Marui NGRS M4 series is an electrically powered M4 with several advanced features built in. Tokyo Marui literally invented the AEG, so with that kind of pedigree you can expect big things from an NGRS M4 platform.
The NGRS works similarly to an AEG, but adds in a moving recoil weight inside the buffer tube, and has a functional bolt catch which needs to be pressed before resuming fire after loading a fresh magazine.
While not even close to the recoil a GBBR provides, the NGRS system gives a nice bit of feedback with each shot, and also has an EBB system which cycles the mock bolt carrier, making the NGRS a bit more fun to shoot than a normal AEG.
With the NGRS system, the bar to entry is high, and NGRS rifles generally cost much more than an AEG, and use their own proprietary magazines which are less common than AEG magazines.
BOLT BRSS M4 AEGs
The BRSS system was Bolt's answer to Tokyo Marui's NGRS M4 platform and adds an even heavier recoil weight to the stock tube to provide rather violent recoil for an electric Airsoft gun.
The Bolt M4 series use standard AEG magazines, meaning mags are easier to find than the TM, but the BRSS does not have the bolt stop function which makes the TM so popular amongst Milsimmers in the Airsoft community.
The internals of the Bolt M4 BRSS AEGs are a unique design, making them more complex to upgrade and source parts for than the ever available AEG parts.
That said, a Bolt BRSS is probably the easiest and cheapest way to get a bit of recoil in your life in rifle form, and can be a good stepping stone between an AEG and a GBBR M4.
Tippmann M4 HPA Series
The Tippmann M4 HPA series is an original design based on tried and tested paintball technology. The Tippmann M4 operates using high-pressure air (HPA) which is contained within a paintball-style air bottle, which is generally carried separately from the rifle itself, tethered to the system via what is known as an airline via a pressure regulator.
The Tippmann M4 feeds from standard AEG magazines, and its air bottle can be refilled via a high-pressure air dive tank, or using an air gun style pump. This means if you have access to a source of HPA the Tippmann can be very convenient, though many Airsofters are put off by the limitations of using an external air source to power the system.
Tippmann's M4s are intended for performance focussed skirmishers and are great shooters when they are set up right, but operating one properly and safely requires more research than using an AEG, which is practically plug and play.
HPA may be very fashionable at the moment, but it is not the best call for a new player just starting the sport. Like a GBBR, a Tippmann is an M4 for the player who has experience and knows what they want to take their hobby experience to the next level.
Why use an M4?
M4s are very popular amongst Airsofters primarily for one reason; they are very popular in the real world too! M4s are issued to the US Army, USMC and several Special Forces branches, and are also extremely popular with civilian tactical and competition shooters in the US.
This has resulted in an aftermarket for the real M4 which gives an almost infinite number of customisation options. The Airsoft M4 platforms follow suit, and usually have the latest and greatest aesthetic parts a month or two after the real M4 equivalent hits the market.
No other Airsoft platform can match the M4 in the way it can be customised, and despite the fact that this platform serves the vast majority of Airsofters today you can still make an M4 which is one of a kind to suit your specific needs.
M4 AEGs are often lighter than equivalent platforms, have simple and easy-to-use controls and broad magazine availability, meaning building a full loadout is often cheaper and easier using an M4 AEG. M4 AEGs use the tried and tested Version 2 Airsoft gearbox which has been around for decades and is known to be a mature design in which any design issues have long since been solved.
Milsimmmers love GBBR and NGRS M4s, primarily for their realistic features such as the functional bolt stop, and the immersive firing experience their recoil systems provide. These M4s are more expensive and maintenance intensive but are a great option for a more committed Airsofter with a taste for realism.
The M4 design has spawned some of the best performing Airsoft platforms available today, from the CQB speed demon G&G ARP-556 to the authentically licenced Krytac REC 7 series, complete with realistic Barrett Firearms markings. M4 AEGs particularly are often at the cutting edge of Airsoft design, and usually boast the latest innovations before they filter down to other platforms.
With a bit more knowledge under your belt you should now know what you need to know to narrow down what kind of M4 platform fits you best. If you want to know more about the M4 and its different parts, check out our platform walkaround for the M4. If you are ready to start browsing and begin your search for the ultimate M4, check out the plethora of M4 rifles available currently below!