By today’s standards, the M4A1 from the AR15 family is a weapon deemed almost archaic due to the lack of picatinny rails and everything that can be mounted on those rails. But, the M4A1 is the proverbial father (…or is it the mother?) of today’s SOCOM version (…Block I and Block II) of combat carbines used by US Forces.

The M4A1 was introduced to the US Armed forces by Colt as an answer for their needs and wishes to phase out the plethora of various sub rifle length weapons from the inventory and replace those with a common carbine length weapon that is as common with the M16 as possible. The basic design dictated a select fire short version of M16 with a full auto trigger group instead of the 3rd burst unit the M16 sports. The specs also demanded a removable carrying handle with rear sights, flat top upper receiver with an integral picatinny rail for mounting optics a shorter barrel that ensured reliable target engagement up to 300m and a collapsible stock.

Colt delivered a well rounded package and was awarded the contract, they registered the name M4A1 and the rest is history.

Airsoft replicas come in all shapes and sizes, while TM was the first to offer the M4A1, King Arms is the first one to offer a quality replica with fully licensed trademarks in a full metal shell at a decent price, that actually rival those of ACM AEG’s.

The AEG comes in the usual King Arms box that ensures safe transportation of the replica. Their entry level AR15 AEG comes in, at the time at least, three versions, M4A1 with 14.5″ barrel, the M4 CQB with a 10.5″ barrel and the M4A1 Fixed Stock again with the 14.5″ barrel.

King Arms deliver the AEG with a small card attached to the AEG, where the model, serial no, test measured FPS, test BB weight, date of test and signature of the tester are given. This is a nice touch, just to make you feel a little better, so one knows the gun has been tested and is fully functional when it leaves the assembly line.

The M4A1 sports original Colt trademarks as clearly indicated on the box, the licensing agreement between Cybergun and King Arms solves any unwanted complications for retailers. The lower and upper receiver come in a bit unusual brown-ish graphite grey color, with clearly deep engraved trademarks, serial and fire selector settings.

As is usual by now all AR15 AEG’s from King Arms have a fully working charging handle, bolt and bolt catch, which is a nice feature to either play with or to adjust the hop-up unit.

The M4A1 is taken apart as the rest of the AR15 AEG’s by simply pushing out the front pin (…which is of the non fall through type, it’s kept in place by a spring loaded pin in the lower receiver, same goes for the rear pin, that has a wire safety on it to prevent a fall through) and just slide the upper an lower apart basically.

The barrel and the front sight section sports the standard side sling attachment point, the front sight also sports a bayonet lug, the unit is pinned to the barrel and additionally secured by an allen screw.

As is usual with the modern AEG, markings are almost omnipresent, OK, that was exaggerated, but, the barrel does have the standard caliber and twist rate marked on it. 5.56 NATO for the caliber and 1/7 for the barrel twist, capable of stabilising the heavier 77gr bullets that are quite common these days, in real combat anyways.

Plastic parts are few, handguard, pistol grip and collapsible stock. The upper receiver sports a flat top with a picatinny rail and a removable carrying handle with a fully adjustable rear sight.

Usuality continued with the moden AR15 series; all upper receiver have shell deflectors for left handed shooters built in as well as forward assists, ejection port covers seem to be a must on a battle carbine of AR15 type.

The HopUp unit is located in the standard position and can be accessed for usual manipulation by pulling the charging handle back, opening the dust cover and retracting the bolt cover, locking it in the rear position.

The HopUp unit is the standard metal one piece version, with the King Arms specific barrel locking insert that has a unique wedge added to it, to lock the barrel a bit more firmly, preventing it to cant within the HopUp unit.

No surprises in the gearbox design and parts used. King Arms is using their standard gear ratio gears for all AEG’s, the pistons seem to be pre-cut in for blowback operation, not that this model has this option, I guess it’s just that the pistons have been brought up to speed, the rest of the AEG not just yet. Personally, I’d forgo the blowback system completely on all AEG’s as it’s a useless gimmick, making the AEG more prone to failure, but that is a whole new can of worms for another review.

A sector clip is installed as is usual on all King Arms AEG’s, a nice feature that increases the feeding reliability. Standard red switch unit, red selector plate and red tappet plate, all parts that have proven reliable and sturdy in the past. Nozzle is standard black. Ample grease is factory applied to the gears, making sure lubrication is present and working.

King Arms seem to be changing the gearbox screws from torx with steep threading to regular Philips with flat threading, this model has the Philips screws with flat threading.

For all upgrade fans, this is a pretty decent AEG with quality internals to use as tha base for your build. The front wiring for the battery is somewhat difficult to manipulate as the mini Tamya connector needs to be removed in order to split the AEG into upper and lower halves. But, this should not be an issue as long as you keep your internals stock. Which you can and they should serve you for a long time. On the sidenote, again, the upgrade fans will be happy to find that King Arms used a Philips screw for the mag catch instead of the allen screw. It would seem the little things really do make life easier.

Magazine supplied with the AEG is the King Arms standard M16 300rd HiCap magazine. It’s a well known design used in the previous models and does the job well.

First impressions are good, the gun perhaps lacks the feel of the more expensive King Arms AR15 models, but nothing serious is missed on this model. As expected no bad surprises can be found on the AEG, chrono shows the consistent 330 fps average with 0.20g BB’s, HopUp unit needs to be broken in which is achieved at about 1000 BB’s fired. After that, the HopUp delivers the expected performance, pretty much what you would expect from a 330 FPS AEG.

The downside to this AEG is the small battery, this only comes into play if you are using the regular, by now somewhat antiquated NiMh batteries, where a small battery (…we used the 1600 mAh) can be fitted in the front handguard.

This is by no means a flaw of the manufacturer but rather a general flaw of the M4A1 as such.

Tha upsides are numerous and by far outweigh the one downside we managed to find. The price is more than attractive, it’s cutting in on the ACM market’s action. Performance is typical King Arms, reliable and consistent. My personal icing on the cake is that it’s fully compatible with Magpul PTS MOE series of parts and it accepts the Magpul PTS PMAG’s without a hickup. Need I say more?

Test item supplied by King Arms

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