When you are brand-new to the world of Airsoft it’s just a lot of fun to kit up with some friends and head out to a local skirmish with whatever you can afford – usually, a cheap, AEG style battery-powered rifle – and see what everything is all about.
After a few skirmishes, though (and maybe participation in a local tournament or two), it’s not hard to get hooked big time into everything that Airsoft has to offer.
That’s when you start to look at some of the better quality Airsoft rifles on the market today (we are talking about high-quality options like the officially licensed M4 from Cybergun, anything from Krytac, or the super impressive Lancer MK 18 clone) that you can tinker with and upgrade all on your own.
The only trouble is that there are so many different accessories out there and so many upgrade options to pick and choose from, and usually, only a bit of cash to go around, that finding the right upgrades that really make a difference becomes a real headache and hassle.
But that’s why we have put together this quick guide.
By the time you are done with the inside information below you’ll have a much better understanding of the best upgrades for Airsoft M4 rifles available, the kinds of upgrades that are going to change your combat effectiveness with this M4 – turning it from a “run-of-the-mill” spooky black rifle that everybody else has to something really special.
Why Kit Out an M4 to Begin With?
There are a couple of reasons to start off with an M4 in the world of Airsoft, but truth be told the same reasons that people are drawn to the AR 15 platform in the legitimate firearms world holds true here as well.
High-quality Airsoft M4 options are well-made, super durable, and have an almost infinite amount of accessories and upgrades available to pick and choose from. You might find a bunch of upgrades available for something like an AEG AK-47 or MP 5, but the M4 will still have those incredibly popular Airsoft weapons beat by an order of magnitude.
Seriously. If there’s something you’d like to do to upgrade your Airsoft rifle the odds are pretty good that someone out there makes a high-quality part for the M4 that you are rocking and rolling.
The only tip we give you before we dive into our recommendations for the best upgrades for Airsoft M4 rifle is that you try and start off with the best AEG for you can afford.
High-quality options like the officially licensed colt, the JG M4, the G&G CM 16 Raider, and the Krytac Trident or Lancer MK 18 are all fantastic starting platforms to really flesh out as you move forward.
Airsoft External Upgrades
Red Dot/Reflex/Optic Upgrade
One of the first upgrades you want to consider is changing out the iron sights that your M4 almost always ships with for either a red dot, a reflex sight, or a true optic that gives you a bit of extra magnification to engage at longer distances.
You don’t need anything crazy, as even fully fleshed out your M4 isn’t going to be all that effective at extremely long ranges (anything close to 100 yards, really) – but these upgrades will change the way to engage, the way that you acquire targets, and the way that you take people down quickly and effectively.
Expect to spend a decent chunk of change on high-quality optics, though. Many of these quality upgrades have 1:1 compatibility with legitimate M4 firearms and carried the price tag to match.
Silencer or Muzzle Brake Upgrade
A silencer, compensator, or muzzle break really isn’t going to do all that much as far as the effectiveness of your Airsoft M4 – it’s really all about aesthetics.
There isn’t any ballistic gas flying out of the barrel of your Airsoft weapon that has to be quieted down, hidden, or compensated for. Everything is running off of electricity and quieting those components down has nothing to do with the silencer tacked onto the end of your barrel.
At the same time, these kinds of upgrades are usually really inexpensive (compared to other options) because they are “vanity” upgrades. They will make your M4 look pretty slick, and that might be reason enough to spend the cash on them.
There are a variety of different or grip options to pick and choose from that will mount to most Picatinny or Weaver-style rails that ship with high-quality Airsoft M4 rifles and a lot of this is going to come down to your personal choice and what you’re looking to get out this upgrade.
Some people (especially those that are used to holding their weapon in front of the magazine well in a vertical kind of position) are going to want to go for a vertical for grip whereas others might want an angled or handgrip that’s a little more minimalist.
A foregrip can improve your accuracy significantly (especially over long ranges) so you want to consider it a performance upgrade rather than a purely cosmetic choice, even if you won’t be fighting off a crazy amount of recoil from your AEG powered M4.
Pistol Grip Upgrade
A lot of quality Airsoft M4 lower receivers are 1:1 compatible with legitimate M4 pistol grips, which means there’s a world of aftermarket options out there for you to pick and choose from.
Plenty of folks opt instead to go with the stock pistol grip that shipped with their M4 just because the differences are pretty minimal, choosing instead to wrap their pistol grip with some stippled tape or rubberized grip tape to get a better handle on their rifle when they are running around the woods.
That’s a really cheap and easy to do an upgrade that will improve your accuracy but will also improve the confidence you have using your weapon in less than ideal weather conditions. There’s no worse feeling than dropping your expensive Airsoft M4 (electric M4) in a mountain stream or in a lake just because your hands were a little slick.
Because the stock is usually where your battery is going to be mounted your options are a little bit limited, as you want as large a battery as possible (in most circumstances) so that you can continue to run your M4 for the entire engagement without losing power or performance.
At the same time, there are a lot of aftermarket companies that make collapsible and adjustable M4 stocks with unique compartments that can squeeze even some of the biggest batteries into them without you noticing – the wiring can get a little bit tricky.
Find something that you’re comfortable with, something that fits your shoulder well, and something that gives you plenty of battery power and you will be good to go.
Airsoft M4 Internal Upgrades
Airsoft Motor Upgrade
Airsoft upgrades can get expensive in a hurry, but there may not be anything that’s going to change the way that your Airsoft M4 shoots more than swapping out the motor.
You’ll have an opportunity to pick between high-speed motors that pump out Airsoft BBs faster than your stock M4 ever could have dreamed possible, high-power motors that are going to make you a whole lot more accurate at longer ranges (especially if you combine these with a new barrel or hop up upgrade), as well as options that try to strike the middle ground as best they can.
This kind of upgrade is really all going to come down to the budget that you have available, the work that you’re willing to put in yourself (wiring is almost always something you’ll have to tackle on your own unless you are shipping the rifle out), and the end results that you’re looking to get out of your “juiced up” M4.
Airsoft Battery Upgrade
Any changes that you make to the motor of your M4 or the gear configuration is always going to necessitate a battery upgrade as well.
The harder you have your drivetrain working the more juice it is going to draw, and unless you upgrade your battery pack you’re going to be chewing through your rifle a whole lot faster than you would have been when it was stock – and that’ll leave you sidelined more often than not.
Battery considerations cannot just focus on capacity, either. You’ll need to think of where you’re going to talk this battery (into the stock or into a fake laser mounted on the rail, for example), heat issues, and how you are going to access the battery to recharge it when you aren’t playing Airsoft.
Airsoft Deans Connectors Upgrade
This is one of those upgrades for any Airsoft weapon that is hotly debated in the community, mostly because some people swear that it changes the way a weapon fires completely and others swear that it does almost nothing whatsoever but carries a pretty hefty price tag.
Deans connectors attached to a specific part of your battery and are specifically designed to lower resistance so that when you pull the trigger you get a better and faster response and a lot more consistency out of your M4, too.
At the end of the day, though, this can be pretty difficult to quantify and may or may not have the transformative impact that a lot of people expect or anticipate it will. It is really all going to come down to whether or not you have the budget for something that may be a little bit unnecessary.
Changing the trigger play on an Airsoft weapon (usually) isn’t going to be super noticeable no matter what.
Hop Up and Bucking Upgrade
Hop up and bucking upgrades are popular options for M4 Airsoft rifles, especially if you have decided to go with a more budget-focused option (like the ones that can be picked up for next to nothing in China as opposed to the more expensive and refined options from Japan, for example).
A hop up and bucking addition can give you a big boost as far as velocity and accuracy are concerned, maximizing the compressed air that your rifle generates while also putting a little bit of backspin on each individual BB as it comes out of the weapon.
You’ll see your effective range increase, your accuracy increase, and your combat effectiveness increases with these upgrades for sure. You’ll also see a huge jump in FPS with these new parts. This will always be important to keep an eye on if you play in tournaments where FPS is double-checked and heavily regulated.
Nobody wants to find their new rifle sideline because a couple of upgrades made it too hot on the FPS scale to use safely.
Inner Barrel Upgrade
If you are going to go down the hop-up bucking route it wouldn’t be a bad idea to throw in a better inner barrel as well.
The overwhelming majority of Airsoft weapons come with a 6.10 mm barrel that may or may not have the greatest quality control straight from the factory. Any variance is going to ruin the velocity that you could have expected from your AEG, which is why a lot of people switch to something that has a 6.03mm or 6.01mm diameter barrel.
Those barrels produce a much tighter fit and improved ballistics. Combined with the hop up and the bucking you get better backspin, you’ll get a better air seal when firing and you’ll see an upgrade of 20 to 30 extra FPS as well.
Upgrading your Gears
A high-speed gear set or a high torque gear set (usually combined with an upgraded motor) can be one of the best upgrades for Airsoft M4 rifles you commit to – but it’s going to cost a pretty penny and will usually involve some elbow grease on your end, too.
Most of the cheap Airsoft rifles coming out of China (and even some of the better M4 rifles coming out of Japan) have cheap plastic gears that like to wear out in a hurry. Add a new motor and a new battery pack to those cheap gears and you’ll chew through your M4 faster than you ever would have thought possible.
Upgrade to high-quality gears (even metal gears) and you’ll not only boost your rate of fire and the reliability of your weapon, but you’ll also get improved trigger response and better accuracy as well. Your M4 will become a whole lot more consistent – and effective – with a gear swap.
Airsoft Shimming Upgrade
As we highlighted above, a silencer isn’t going to do much to quiet down an electric-powered M4 in the world of Airsoft – but that doesn’t mean that you can’t quiet things down considerably while improving the reliability and effectiveness of your M4 with a different approach.
Shimming your gear set (especially an improved gear set) makes everything run within tighter tolerances, producing a smoother operation that also runs a lot quieter than a stock M4 ever would have.
You’ll reduce the amount of wear and tear on your gear sets as well. This in turn reduces the wear and tear on your motor and eliminates the overdrive you put your battery through. All of that adds to extending the life of your Airsoft weapon significantly.
Airsoft MOSFET Upgrade
If you are comfortable soldering and doing a little bit of wiring (and we mean a little bit of wiring) that is not a bad idea to look into getting a MOSFET upgrade module that you can squeeze into M4.
This specific upgrade is going to bypass the level of resistance created in your trigger connection, providing more direct power to the motor that immediately increases trigger response, improves overall efficiency, and even lets you take advantage of 11.1 V LiPo batteries.
Unlike some of the other minor upgrades, we have highlighted above this one has a direct translation to combat effectiveness, something you’ll notice and pick up on as soon as the upgrade has been completed.
You have to be a little bit careful you decide to overhaul the piston that your AEG M4 runs.
For one thing, the piston is the “heartbeat” of your Airsoft rifle. It’s what propels your Airsoft BBs downrange to begin with and if it isn’t the right piston for your needs you’re going to end up with an M4 that feels like a limp piece of pasta rather than a powerful and effective combat rifle.
Half-tooth pistons have a small portion of the teeth that are molded, generating better torque (especially when you have a higher gear ratio) that maximizes compression in the mainspring. This is for folks that want sky-high FPS levels.
A full-tooth piston is better suited for speed players, those that are looking to get a lot of rounds of the barrel as quickly as possible.
If you’re building an M4 with CQB in mind, this is EXACTLY the kind of upgrade you’ll want to seriously consider.
Short stroke pistons can generate a magnitude of compression the other options cannot while shorting the distance the piston actually travels. This reduces wear and tear, improves FPS, and generates higher levels of torque to give you the best of all worlds – improved round speed and a higher rate of fire.
If you’ll be making a piston upgrade it’s probably best done in conjunction with new heavy-duty gears, an improved motor, and a new battery. A piston swap isn’t the kind of upgrade you want to make in a vacuum.