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    Apex Airsoft MK13 MOD 4 EBB AEG


    Apex Airsoft MK13 MOD 4 AEG Review by Booligan

    Table of Contents:
    Basic Gun Information
    First impressions/Packaging
    Gun Specifications

    Apex Airsoft is a relatively new airsoft company offering a variety of M4 based AEG replicas packed with features at a relatively affordable price. With a metal body, free float rail system, and well equipped internals, the Apex guns are a great option for players and collectors alike. I'll be going over this gun inside and out, so keep reading to find out more about this line of AEGs!

    I initially heard about the Apex line of guns through WeaponBlender, who carries the MOD 5 variant HERE, priced at about $280. I got in contact with their distributor, 6mm Gunworks, who sent me the MOD 4 being reviewed today. They have it available HERE, priced at $299. There are several variants available in long and short lengths and with different rail and sight options, so you should be able to find one that fits your tastes.

    Basic Gun Information:
    The Apex line of guns really do come with a laundry list of features. They come equipped with a full metal body, modified V2 gearbox with a shuttle driven blowback system, rotary dial adjustable hop-up, functional bolt catch, and ambidextrous magazine release. They also include some high quality accessories including Tango Down style rail covers and vertical foregrip. The kit does not include a battery or charger, so you will need to provide your own before you can use the gun.

    First impressions/Packaging:
    Apex's packaging consists of a basic foam lower with a cardboard lid. It's a simple package, but it did the job well in getting the gun to me safely. The foam lower has cutouts for the gun and all of the accessories, so you don't need to worry about things flopping around the box during shipment.

    Click on the individual thumbnails to see the full size photos

    Box art
    Sticker showing the model held inside

    Along with the gun itself, Apex includes the aforementioned TD style accessories, a cleaning/unjamming rod, and a manual explaining the features and proper use of the gun. Just add your choice of battery and ammo and you'll be ready to go!


    Gun Specifications:
    Weight: 6.75 lbs
    Length: 31.5" - 35"
    Width: 2.1"
    Height: 10.75"
    Sight Radius: 17.5"
    Length of Pull: 11.5" - 15"

    The Apex MK13 is a full metal replica as the only polymer components are the stock, pistol grip, and included rail mounted accessories. Everything else is made of metal and has a great fit and feel. The whole gun has a matte black finish applied to add to the realistic look. The balance is quite good, albeit a smidge front heavy due to the full metal front end.

    Overview, right side
    Overview, left side

    The MOD4 has a crane style stock which acts as your battery compartment. It's very easy to access the battery compartment by pushing the tabs at the bottom of the rubber butt pad and popping it off of the main stock assembly. The metal buffer tube is a 6 position unit with a real-steel type castle nut that may require tightening from time to time. A 3 hole style sling plate is installed between the buffer tube and receiver.

    Battery compartment
    Buffer tube
    Sling mount

    The receiver is a relatively standard M4 unit with standard controls, aside from an ambidextrous magazine release. The upper receiver is a "slide off" type unit making disassembly a piece of cake, especially since it is rear wired. The magazine release is a real-steel type unit so you must first remove the bolt catch before unscrewing it.

    Receiver, left side
    Receiver, right side

    The pistol grip is a Tango Down type unit with a comfortable design and aggressive texturing to help you keep your grip. The base is a ventilated metal unit with a large flat head adjustment screw.

    Pistol grip
    Motor adjustment plate

    This is an electric blowback unit, utilizing a piston driven shuttle system to move the bolt while firing. There is no recoil to speak of, but it is a nice little extra that can be easily disabled if desired. Simply open the gearbox and cut off the part of the shuttle that grabs onto the piston and you won't have blowback anymore. The gun also has a functional bolt catch, allowing you to lock the bolt back for easy hop-up adjustments. Push down on the bottom of the bolt release button while pulling the bolt back to lock it, and push the main button to release it.

    Bolt locked back

    The front of the gun features a free float KAC style rail system for mounting accessories. It's made entirely of metal and does add a fair bit of weight to the front of the gun, but the overall balance isn't bad. The rail has zero wobble or free play and can be adjusted if needed for proper alignment.


    The outer barrel is made of metal and also has zero wobble or free play. It is terminated in a 14mm- threaded muzzle which is fitted with an orange painted flashhider. Apex also attached a small faux gas block on the barrel, inside the RIS, but there is no fake gas tube to make it as realistic as it could be.

    Outer barrel
    Low profile gas block barely visible

    Flip up iron sights can be found front and rear, allowing you to easily aim this rifle. The sights lock in the upper position, requiring you to push the small button on the side to fold them. You also have plenty of rail space for mounting optics if desired.

    Rear sight
    Front sight
    Rail space

    You'll find several trademarks molded and machined onto the lower receiver, including a unique serial number. Strangely, they have markings on both side of the lower receiver showing that the gun was made in Hong Kong. Seems a little overboard, but hey ,we'll never forget that this came from Hong Kong.

    Right side magwell marking
    One of two Made in Hong Kong markings
    This really is begging for a Triforce to be added
    Unique serial number, mine is number 41

    The included magazine is a full metal hi-cap which holds about 300 rounds. It feeds quite well but does have some side to side freeplay when inserted into the magwell. Thankfully, this thing will fit damn near any magazine you can throw at it, and other magazines fit much better. I was very pleased with my magazine compatibility testing, as I tested magazines from JG, Echo 1, DBoys, APS, G&G, G&P, MAG, ICS, KWA, VFC and Star and didn't have any fitment or feeding issues. This thing really does fit pretty much anything.

    Feeding end
    Winding wheel. Nothing too exciting here.

    Performance after a 500 round break-in, using ASGI G4 .20g ammo is as follows:
    High FPS: 428.5 FPS
    Low FPS: 421.0 FPS
    Average FPS: 425.2 FPS

    Rate of fire using a Tenergy 11.1v 1000 mAh 20C LiPo pack came in at 18 RPS, which isn't terrific, but is certainly quite skirmishable. For higher ROF, you can disable the blowback and add a higher speed motor and you'll be good to go.

    Range and accuracy, tested using some heavier weight Echo 1 .25 and .28g ammo was pretty damn good. At 175', I was putting my rounds on my torso sized target with 90% consistency. At ranges further than that, the shots tended to start breaking from side to side. I imagine that with a different nub design, you would see this range extend out to 190'+.

    Inside the MOD 4, you'll find a modified V2 gearbox with accouterments for a QD spring guide and the aforementioned shuttle driven blowback system. Disassembly isn't too difficult, however, you do need to remove the bolt catch assembly by tapping out the pin on the side of the receiver before you unscrew the magazine catch. After that, the disassembly procedure is standard M4.

    Gearbox, right side
    Gearbox, left side

    The gearbox is fitted with a metal selector plate and 9mm ball bearings. The faux bolt is attached to the shuttle which rides inside the gearbox on a rail. The cylinder window has radiused corners for durability and to prevent gearbox cracking.

    9mm ball bearings
    Shuttle track
    Radiused cylinder window

    Inside the gearbox, you'll find steel gears, a polished cylinder with a single port, an aluminum cylinder head with rubber cushion, a piston with aluminum piston head, and a plastic air nozzle with inner O-ring. Everything is pretty well shimmed, however, they did apply a bit too much lube on the gears in my opinion. The airseal is great, with almost zero movement possible with the cylinder head plugged.

    All opened up
    Steel gears
    Piston teeth, only 1 steel tooth
    Cylinder and cylinder head
    Rubber cushion
    Air nozzle with inner o-ring

    The spring guide is a QD unit allowing you to easily change the spring without fully opening the gearbox. You still do need to remove the gearbox from the gun before removing it though.

    Spring guide

    The hop-up is a metal one piece unit with a large rotary adjustment dial. The inner barrel is a 6.03mm tightbore unit which appears to be made of stainless steel. The nub and bucking are standard units that work quite well at the stock power levels.

    Inner barrel and hop-up
    Hop-up unit
    Standard nub design

    The motor is a long type, standard torque/speed unit with standard strength magnets. Nothing really revolutionary, but it gets the job done. The rest of the electrical system is quite nice with very high quality wiring and plugs.

    While the Apex does come well equipped, we airsofters do love to tweak our guns to fit our specific roles or tastes, and that is very easy to do with this model. In my case, I'll probably end up changing a few parts around to make it into a bit of a long range rifle, but externally, I'm quite pleased with this thing out of the box.


    Full metal construction
    Comes with high quality furniture and accessories
    Field ready performance out of the box
    Runs very well on an 11.1v LiPo
    Plenty of rail space for mounting accessories
    Well equipped gearbox
    9mm ball bearings
    Quick change spring system
    Crane stock is a bit larger than others and fits batteries better

    Mechanical blowback isn't the best system, but is easily defeated if wanted
    No battery or charger included
    Ambidextrous magazine release can be a little notchy sometimes
    Some magwell wobble

    Having never tested or even handled the Apex guns, I had no idea what to expect upon opening that box. It does seem that they did a great job putting this thing together, as it has zero creaks, wobbles, or other detrimental issues to speak of. Cosmetically, it looks fantastic and internally, I can't really find anything major to complain about. The blowback doesn't really add too much to the overall feel or function of the gun, but it is quite easy to disable if so desired. Overall, I'm quite pleased with the product that Apex put out with the MK13 series, and am excited to see what else they end up putting out!

    Many thanks again to 6mm Gunworks, WeaponBlender and of course, Airsoft Retreat!