Anyway it has been a couple of weeks since I picked up the Combat Machine M4A1 (G&G’s entry level brand) and decided to take it apart today, or at least I did as much as I could but more on that later.  Let’s recap what comes with the gun…

The Combat Machine M4A1 comes with a 450 round high capacity magazine, ~1000 rounds of 0.2g BBs and a cleaning rod.  The M4A1 is pretty plain with a standard M4 heat shield handgrip, detachable plastic carry handle and a six position LE stock. As the box indicates the CM M4A1 also supports G&G’s new pneumatic blow back mechanism which gives the gun a bit of novelty, even if the feature doesn’t really do anything. Out of the box, the gun chronies at 320 fps with 0.2g BBs according to my Guarder Speeder 2000.

As with all regular M4A1 AEGs the battery goes into the handgrip and to keep the cables in place and tidy, G&G zip ties the battery cable to the outer barrel. To access the hopup, pull on the charging handle and the dust cover will flop open.  That will also pull the fake bolt back which allows you adjust hopup dial. Combat Machine is G&G’s entry level brand and as you can see from the third picture the gun comes with a three piece outer barrel. That was a bit disappointing, I guess eventually this gun will suffer from the dreaded barrel wobble problem. Also note the front section of the outer barrel is made from a single piece of cast metal so you’ll need to get a new front sight if you want to install a single piece barrel.

Removing the upper receiver of the Combat Machine M4A1 is the same as with Classic Army, G&P and of course G&G M4s. The Combat Machine M4A1 uses a hybrid version 2/3 mechbox and cracking this shell will be difficult.  It has a lot of  metal up front where the cylinder head is and is not affected by the design flaw that affects Version 2 mechbox shells.

The front pin is hinged which is a nice feature, now you don’t have to worry about losing that pin.  The hopup unit is one piece and made of plastic.  The barrel is made from aluminum and from what I’m told it’s standard bore (6.08mm). Another neat feature with the Combat Machine M4A1 is when you press the forward assist button, it releases the anti reverse latch which allows the spring to fully decompress.

Here’s a close up of the blow back mechanism from the outside anyway, I wasn’t able to get into the mechbox so I’m not sure how it works internally.  I am told from a friend who was able to take apart his gun that there’s a hole at the top of the mechbox and which diverts some of the compressed air from the cylinder into the black tube which pushes a piston attached to the fake bolt.

I’ll admit that it’s certainly neat but it wears off quickly. When the gun is empty the bolt only moves back a couple of centimeters but when loaded the bolt moves as far as the above picture shows when I pull the charnging handle back. You can’t lock the fake bolt back with the Combat Machine M4A1 but I believe you can with the G&G and Top Tech M4s with support this feature.

After seeing G&G cut corners with the Combat Machine M4A1, I was pleasently surprised to see the pistol grip has brass inserts for the motor plate screws, that means it’ll never strip. The mag catch comes apart like with a real M4 and the motor is the standard long type.

The reason I was not able to get into the mechbox is because for some reason there’s a piece of plastic in the groves of the buffer screw.  My screwdriver just can’t grab it. 🙁  Very disappointing, if I figure out a way to remove the plastic I’ll rip the mechbox out and snap some pictures.

The Combat Machine M4A1 feels pretty solid and if I were a novice entering the hobby I’d have no qualms using a weapon like this.  As a loaner I feel comfortable that I’ll be lending friends something reliable and if it breaks it’s not that big a deal since it was cheap. 😉  At the end of the season (or when something pops up) I’ll post an update on how the gun performs.