You don’t get a lot for €20, especially not in the world of replica guns. So, when I visited a boot sale recently and discovered a man with (literally) a plastic bucket filled with half a dozen or so well-used airsoft AEGs, I was immediately interested. All of them showed signs of hard use with rusty fasteners and cracked and broken plastic. But one caught my eye. It was a replica of the iconic M4A1 that had good weight, everything seemed to be there (including the magazine), the plastic parts were in good condition and it was fitted with a simple Swiss Arms reflex red-dot sight in place of the carry handle.
However, it lacked batteries, the buffer tube and stock were flopping around loose and appeared to be retained by a great deal of black insulating tape, the red-dot didn’t switch on and when I asked if the AEG was working, the answer was, “probably”. And a smiling shrug.
I asked how much? He said €25. I offered €20 and he agreed. So, I unexpectedly found myself the owner of an AEG of completely unknown provenance. There was nothing on it to suggest who it was made by and no certainty that it worked at all. But hey, for €20 at least I’d have a red-dot sight that I could use on my Umarex G36C. Probably… Let’s see if I bought some cheap fun or an expensive source of spares for my other replicas.
Back in the early 1950s, the US Army began a truly futuristic project to develop a totally new infantry weapon. The SPIW (Special Purpose Individual Weapon) was planned as a fully automatic rifle that would fire not conventional rounds but steel flechettes at an astounding 2,300 RPM and from a weapon weighing only 3lbs. However, the project was dogged with problems and in 1964, the US Army instead adopted a modified version of the ArmaLite AR-15 assault rifle as an interim solution until the SPIW was ready.
The futuristic Springfield Armory SPIW. It never got beyond the prototype stage.
The AR-15 became the M16 in US Army service, just in time for major American involvement in Vietnam, which didn’t work out terribly well at first. Early M16s, particularly when they were used in the heat and humidity of Vietnam, proved susceptible to corrosion and frequent jamming. Eventually, these problems were addressed and the M16 became the principal infantry weapon of the US Army when the SPIW project was finally dropped.
A US Army soldier in Vietnam with the then-new M16
The M16 finally proved to be reliable and effective, but it was always intended as a full size infantry rifle. However, Colt (who had purchased the rights to manufacture the AR-15) also later produced a carbine version, the CAR-15, which featured a telescoping stock and a 14.5 inch barrel compared to the 20 inch barrel on the M16. Initially, the CAR-15 was issued to crews of armoured vehicles and helicopters, where its reduced size made it easier to store and use.
A US Special Forces Delta operator with a CAR-15 during the First Gulf War in 1991
However, several US Special Forces units also began to use the CAR-15 and discovered that the slightly reduced muzzle velocity provided by the shorter barrel wasn’t a major issue. Soon other US military units became interested in this handy carbine version of the M16. Before long, it was adopted by the US military first as the M4 Carbine (with semi and 3-round burst modes) and later as the M4A1 with semi and full auto modes. Experience in Iraq and Afghanistan proved the worth of this weapon and now, variants of the M4 are used by most US Army and Marine Corps units.
US Marines training with M4A1s
First step – assessing the problems
Three functional problems were immediately apparent on examining this well-used M4A1 AEG. First, the buffer tube was loose, allowing the stock to flop around. In an effort to fix this, the previous owner had wound a great deal of black insulating tape round the base of the buffer tube, but this didn’t really address the problem. Second, when I got home and tried fitting a battery and pulling the trigger, nothing happened. Third, the red-dot sight didn’t work. This last issue is a real problem as this didn’t come with the M4 carry handle that incorporates the rear part of the iron sights, so I need to get the red-dot working.
In addition, there are a number of cosmetic problems. Almost all fasteners and metal parts such as the buffer tube collar, the ejection port cover and the front of the handgrip are lightly corroded. Most of the plastic is faded and grubby and there are stickers and the remains of stickers on the receiver. If it’s going to look half-way decent, all these things will have to be addressed. On the positive side, the receiver is in generally in good condition and none of the other plastic parts are cracked, broken or missing.
Finally, I have to work out what I have bought. I can’t see a manufacturer’s name anywhere on this replica. The receiver is heavy plastic with nicely engraved Colt markings and the battery fits inside the handguard which is split vertically. The magazine release and telescoping stock work as per the original and the charging handle retracts, though all it does is open the ejection port to give access to the hop-up adjustment. The forward-assist on the right side of the receiver moves, though the spring-loaded button doesn’t do anything.
The whole replica, with magazine but without batteries or BBs, weighs just over 2.6kg. After a great deal of looking at photographs of AEGs (the M4 and its variants must be one of the most common AEGs), I believe what I have here is a King Arms M4A1 Ultra Grade. King Arms are a Taiwan-based manufacturer of airsoft replicas and accessories and this particular replica seems to have reasonable reviews which makes me think it’s worth trying to refurbish.
Fixing the loose buffer tube
The first job is to fix that loose buffer tube and stock. After removing yards of black tape, nothing is obviously broken which is a good thing, but the base of the buffer tube and the adjustable collar aren’t sitting firmly against the rear of the receiver as they should.
All that insulating tape wasn’t actually doing much… You can see here the gap between the base of the buffer tube and the rear of the receiver and that the buffer tube can move from side to side. The screwable collar on the buffer tube should be flush with the plate on the rear of the receiver.
The plastic stock is removed by pulling the adjustor down all the way and sliding the stock off the end of the buffer tube. This then reveals an end-cap that is secured by a small hex screw.
Looking down inside the buffer tube with the end cap removed reveals a cross-head screw. Unscrewing this allows you to remove the buffer tube.
With the buffer tube and retaining screw removed, the problem is clear.
Someone has replaced the retaining screw with one that has the correct thread but is much too long. You can see where they have tried to force the blank part of the screw into the threaded part of the receiver. When this hasn’t worked, they simply wrapped a length of insulating tape round the base of the buffer tube to hold everything in place. Happily, this bodging hasn’t damaged the thread in the receiver and simply swapping for a screw of an appropriate length fixes the problem completely.
Well, that was easy! If the rest of this refurb is as simple, I’ll be very happy indeed.
But, in the next part I’ll be doing something that I don’t enjoy at all when I take a look at the electrical side of things to try to find out why this AEG won’t shoot.