TOP TECH: M4 Carbine

Announcement of blow back replica M4 from Top Tech generated a impressive buzz in the airsoft community. There were many questions and this review is written with sole purpose to offer answers to this questions and to dispel some rumours, floating around. Solution of blow back system is very interesting- it is not mechanical (with link between piston and bolt) but pneumatic.

One of the most often asked question is who exactly is Top Tech ? What is their connection with Guay Guay? And most importantly, are they products any good?

Well, manual answers on first two questions (and rest of this review on the second): Top Tech is anauthorized user of G&G patents and technologies. Quote indicates that they are in very close business relationship, where Top Tech is specialised in electric blow back replica and Guay is focused on classic gearbox technology.

Currently, Top Tech is specialized on electric blow back replicas. Their idea of blow back pneumatic system is delightfully simple. It diverts certain amount of air from the cylinder to smaller cylinder at the top of the gearbox with attached fake bolt. It is efficient and most importantly, very reliable.

Currently, four pneumatic blow black models from TopTech are available (M16A2, M4 Carbine, M4 Commando; fourth T614 was introduced later than first three models). Also, there will be MP5 series available at some point. And they all share pneumatic blow back system.

Back to the review of Top Tech M4 Carbine. We are talking about M4A1 and It is kinda hard to be extra creative when writing about M4A1, since M4 is probably most prolific model in the history of the airsoft. As much as I dislike commenting the boxes, TopTech’s M4 Carbine box is a piece of art. Its slick presentation hints that is stores something special. Box contains replica, HiCap magazine, manual, small packet of BBs, front sight adjustment tool and armourer’s wrench.

Hicap magazine is typical HiCap, but with a twist- its capacity is 450 BBs and not standard 300 BBs. Despite additional length it feeds reliably. Also, replica appears to be compatible with all major brands of magazines.

Markings are pretty much made up. Replicas are equipped with receivers with SFOD-A, Green Berets, USMC and SEALS logos. Guay Guay (and therefore TopTech) does not have any agreement to use licensed trademarks. Still bit better than GuayGuay’s logo with Greedy island inscription.

As almost every AEG these days, replica is full metal. Finish of the body is on par with all the other top tier manufacturers- it does not chip, even after more rigorous use. Different colouration of metal parts is also worth noting.

Plastic parts (fore grip, stock) appears to be quality products. Law enforcement type telescopic stock has 6 different settings. Battery is stored in fore grip. Manual suggests that we use either 9,6V or 12V battery packs. We used 8.4V battery and it worked flawlessly without any adverse effects.

Again, there is no denying that Colt/Armalite family is done to death. Almost every conceivable model is readily available, which means that manufacturers must focus either on low prices or on new, innovative features.

And Top Tech did the latter. Replica has -in addition to blow back gearbox- several features, which make Top Tech’s models stand out from the crowd of the similar models:

– first such feature is moving fire selector indicator on the right side of the body. This maybe a small thing, but it shows dedication to details. It can be done, so why it hasn’t been done before?
– second feature is moving bolt. Due to construction, magazine with BBs must be inserted in order to achieve full blow back (when replica is dry fired, blow back is much weaker).
– Third feature is spring release, which is accomplished via pushing the forward assist knob. Another feature, which is fairly simple to implement and can greatly extend the service life of both spring and gearbox.
– Fourth feature is working bolt catch, which is now more and more common feature in AEG replicas.

HopUp adjustment is pretty much standard for any Colt/Armalite model. Pulling the charging handle reveals HopUp dial. HopUp chamber is plastic, which is not bad- at least in the bitter cold of the winter, as plastic chambers appears to be less affected by cold.

Top Tech/Guay Guay turned a new page as far as quality control is concerned. Replica works flawlessly for about 10.000 BBs, so any short term problems should become apparent by now.

Taking apart is simple endeavour an even with additional features is causes no problems (all such parts are located on gearbox shell). Save for the blow back cylinder, there is no additional parts inside the gearbox, so there should be no problems regarding compatibility with aftermarket parts.

Parts inside gearbox are fairly standard, but there are several parts, which should be mentioned (as they are on TopTech’s webpages and manual). First, copper cylinder head is used in order to reduce the consequence of long term friction of the traditional plastic cylinder head in causing with the change in air density level and decelerate the energy of gear turning.

Top Tech also used CNC cut steel for nr. 2 torque gear (aka sector gear). This naturally decreases wear and tear.

Wires are often overlooked part of airsoft replicas. But not by Top Tech. They use silver electroplated wire set in order to minimize resistance and offer better battery efficiency.

Gearbox uses 8mm ball bearings. As you suspect, turning is very smooth. Piston head is CNCed from AL6061 (aluminum) in order to maintain good compression and stable exit speeds (slightly less than 100 m/s with .20g BBs).

Another feature, worth mentioning is selector plate, made with MIM process. MIM (metal injection moulding) is fairly new technology, which uses combining of fine metal powders with plastic binders (thanks, Wikipedia!).
While unimportant at the big picture, it is cool to show that manufactures are actively using new technologies in order to make products more durable and wear resistant.

TopTech M4 Carbine is very pleasant to use in airsoft skirmishing. It has all the positive properties of the real world counterpart (abundance of accessories, compactness) and new features make this replica a dependable companion on the field.

We experienced only couple of minor mechanical problems. First was loose fire selector, and second was loose buffer tube. Both are easily correctable, but it appears that vibrations do have some adverse affects.

First M4A1 AEG with electrical blow back is here. Whole system is very sound and does not cause extra stress to gearbox shell or inner parts. I was especially interested in durability of blow back mechanism, but its simple design dictates that it shouldn’t cause any headaches.

Blow back is relatively weak and does not resemble real blow back by any stretch of imagination. Blow back is weaker than blow back with Guarder type blow back system (meaning that movement of bolt depends on piston’s movement).

Replica slightly vibrates, which gives feedback that something is happening at the business end of the replica. Solution is more durable than previously mentioned mechanical solution and moving bolt is an excellent eye candy.

Are these new features gimmick or actually useful features? Stance of Airsoft News EU staff is pretty uniform that while blow back is a nice feature it is not necessary one. Others (fire selector indicator, spring release) are more useful and it is crying shame that they weren’t implemented yet.

It will be interesting to see how will next models from Top Tech be received. D?but of pneumatic blow back system (accompanied with other features) is impressive and we eagerly await other models. Family of MP5 replicas is already announced- and I don’t think Guay Guay and Top Tech will stop there. And they shouldn’t, as they have solid and mature product to offer.

Test item provided by TopTech

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