AABB Glock "KOO" Carbine Kit and 50 Round Extended Magazine review by Booligan
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Table of Contents:
There has been a recent surge in popularity with Glock carbine conversion kits, and AABB is one of the main manufacturers of a variety of kits. This kit is similar to the FAB Defense KPOS conversion kit, however it differs in certain design elements and materials used. It is available for KWA/KSC G18Cs, TM G18Cs, and TM G17 models, however I believe the TM G17 kit will work on other G17 replicas out there. I will discuss all of the details of this kit, which I installed on a KWA G18C in this review!
I obtained this carbine kit as well as an AABB 50 round extended magazine through Evike, who is the first large US based retailer to stock it. The KWA model is available HERE, with the TM G18 and G17 GBB models being available HERE and HERE, respectively. The kits all cost $80, and the magazine being reviewed is available HERE, priced at $38. Obviously, you will still need the base Glock GBB to use with this kit, as it is not included.
The "KOO" Defense Carbine kit is a way to basically drop your existing Glock GBB into a receiver that adds a side folding stock as well as several rails, making it into a submachine gun (if your gun is already full auto). The benefits of this are increased accuracy as well as the ability to use electronic sights, lights, lasers, foregrips, or other accessories. The benefit of this kit is really the side folding stock and small overall size compared to some of the other carbine kits on the market. This kit uses a high strength polymer receiver with metal parts wherever it is necessary, such as the folding stock and the locking assembly that holds the gun.
I received the gun a few days after ordering it through Evike using UPS ground. It arrived in a fairly small box, and upon opening it, I discovered that the kit came entirely disassembled, requiring me to basically build it from scratch. Assembly was fairly straightforward, only requiring a few basic hand tools.
Along with the carbine kit itself, AABB included a metal RIS mounted sling point and a folding foregrip that doubles as a safety device, as it can be extended to cover the trigger. I prefer to use a lower profile RVG foregrip, so all of the pictures have that foregrip installed.
From this point on, click on the thumbnails to view full size photos
Weight: 2 lbs (about 3.5 lbs with pistol installed)
Length: 13.6" - 22"
Height: 5.75" (standard mag) – 9" (extended mag)
As mentioned before, the body of this conversion kit is made out of a high strength polymer as opposed to aluminum on the real steel conversion kit. The stock is made of metal with a rubber butt pad for comfort. The kit attaches to the donor gun at two points, the first being the front rail and the second being a sliding locking piece at the rear. If you are using a select fire Glock model, you must install the included low profile selector switch. Directions for this can be found on Youtube.
Carbine overview, left side
Low profile selector switch installed
Rear locking piece
The stock itself is made of a non-ferrous metal with a plastic and rubber butt pad. It it attached to the body of the conversion kit with a metal hinge that requires you to pull down on the stock to fold it. When the stock is extended, there is a fair amount of wobble and free play, so I've added some velcro to help fill the gap between the stock and the body and minimize the wobble. The hinge lock is fairly stiff, so it won't accidentally fold or unfold during use.
Folded, still allows access to the trigger
The body of the kit itself is fairly strong, but if you really torque it, it will bend. I've yet to be able to bend it enough to disrupt operation of the gun, so I'm not terribly concerned about it. The cocking handle is located on the left side of the body and it attaches to the gun using a plastic piece that fits over the rear sight. You can still access the slide lock with the kit installed, however you cannot access the selector switch, so you must take the gun out of the kit to change fire modes.
Handle locked back
Cocking handle mounted on rear sight
At the front of the kit, you will find rails at the 12, 3, 6, and 9 o'clock positions, allowing you to mount all manner of accessories. The rails are made out of plastic, and the side rails are removable. The bottom rail is split and doubles as housing for the front locking crossbolt. The crossbolt is a unique design that has a notch cut out of the rod, allowing you to rotate it 90 degrees so the gun can slide in, and then rotated back and locked to hold onto the notch on the gun's rail.
View of the cutout in the locking lever rod
At the very front of the kit, you'll find a large metal compensator. This can be removed if you are using the kit with a threaded barrel and mock silencer, however the screws are the ones that hold in the side rails, so they will probably need to be removed if you are going to run the gun without the compensator.
Shot into the compensator, showing the barrel alignment
Installing the kit is a relatively simple affair, requiring you to first rotate the front locking lever so that the gun can slide in unimpeded. You will also want to tap out the lower pin on the stock hinge assembly, and pivot the stock assembly up, sliding out the rear locking piece. Slide the gun in and rotate the lever, locking it in place. You can then slide in the rear locking piece, which slides over the rear of the frame of the donor pistol. This piece is secured by pivoting the stock assembly back down and replacing the pin. The cocking handle must be in place inside the kit, and the gun will lock into it once you place it inside.
Punch out this pin first
Then pivot the stock up and remove the locking piece
Kit without gun installed
There are no trademarks on the carbine kit at all. There's not even a single "Made in China" marking to be found.
In addition to the carbine kit, Evike sent the Matrix/AABB 50 round extended magazine, which is styled after the 31 round extended magazines available for real Glock pistols. The magazine has full trademarks and markings indicating the real capacity (31 rounds), and includes a plastic extended baseplate. On mine, the baseplate was cracked on the side, making it quite unstable, but I've repaired it using superglue. I've mounted the extended baseplate on my standard length magazine, and the flat baseplate went on the extended mag, as I like the way both mags look with those baseplates.
Gas fill port
Extended base plate
Crack in the baseplate
The mag feeds well, but it was having a problem holding gas when I first got it. It filled just fine, but the knocker valve was leaking it out slowly. I figured it was from dry O-rings due to sitting on a shelf for a while, so I took the valve out and soaked the whole thing in 100% silicone oil overnight. I then reinstalled the valve, and it held the gas just fine.
Being that this kit adds a multitude of rails to your otherwise boring pistol, the sky is the limit as far as accessory use. I've gone with a simple T1 style red dot sight and RVG grip at the front. You can remove the front compensator and mount a can to your gun if you have a threaded barrel, or if you have an extended slide model. There are plenty of upgrades available to the various Glock pistols themselves, so you can turn this into a little CQB monster with the addition of a few simple parts. I've installed a stronger recoil spring, which has raised the ROF substantially.
Adds a stock and rails to your pistol
Includes folding grip and metal sling mount
Folding stock for compact storage or concealment
Stock is stepped down to allow use of low profile sighting systems
Overall size is quite small and lightweight
Includes low profile selector switch
Polymer construction has some flexibility
Can't change selector switch while gun is installed
Non-ambidextrous cocking lever
No included sights
I really like the idea of throwing the versatile Glock G18C platform into a more stable base and using it as an SMG. Of the various kits out on the market, I personally think this kit is the most versatile, as it has a side folding stock for concealment and compact storage. The HERA arms type kit is a close second, but I don't like the fact that you have to use high profile sights with that model. The stepped down stock of this model allows you to use low sights, such as the T1 pictured on mine. Overall, with this gun setup and a few extended mags, you will be a force to be reckoned with on the CQB field!
Many thanks again to Evike, and of course, Airsoft Retreat!