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WE/Cybergun M1A1 Thompson Submachine Gun

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As some of you already surmise, I sold my dignity and purchased something from Cybergun. As the only Tommy GBBR I felt my wallet cornered though to be fair this is not my first CG purchase as I also got the WE/CG Desert Eagle last year so you could say I didn't have any self respect in the first place. So with that, on to the review.

The gun is a truly open bolt submachine gun with select fire capability doing about 330fps (30C) at around 850rpm. When out of bbs the bolt locks to the rear until a loaded magazine is inserted and the charging handle pulled back. It is full metal with the major parts (barrel, receiver) in aluminum anodized in a beautiful parkerized look, however it's worth noting that all Thompson SMGs from 1928s to M1A1s left the factories in a blued or du-lite finish. Parkerization was done at the US armorer level and only when returned guns needed refinishing so completely parkerized guns were rarely ever seen until after WW2. The internals are a cast zinc alloy however the sear and bolt have steel reinforcement inserts where they engage against each other for better wear resistance. It has faux wood furniture in ABS plastic and while visually appealing, has a very hollow sound and feel to it especially when the rear sling swivel rattles about. You could, I suppose, fill the plastic with expanding foam or even body filler/bondo to make it more solid and add some heft as the total weight of the gun with the supplied 50 round magazine (30 in real life) only tips the scale at about 2.8kg. Because of this I've changed the furniture out with real walnut by Black Owl Gear. They are the cheapest commercial kit available though need to have the screw holes drilled out first. They go on without modification however the handguard does not sit completely flat against the barrel and will require some sanding to get it really squared on. Speaking of sanding, the kit is roughly finished giving it a very plain and uniform look. I've refinished mine by sanding it down to 400 grit, re-staining in walnut and coating with a couple coats of clear lacquer for water proofing. Installed, the kit adds about 500g and while still over a kilogram short of the real gun's weight, gives it a much more solid, confident feel to it. There are steel kits available now which brings the gun to true weight however they cost over $900






Internally it has a 270mm inner barrel and of the modified VSR-10 kind which is to say if you plan on changing either the barrel or hop rubber, you have to swap out both. It doesn't shoot bad considering it is a submachine gun, but I did have to correct the crown which was a bit eccentric and was causing turbulence at the muzzle affecting group size. With that sorted it groups within an A4 size sheet of paper at 20m. The sound when firing is fairly loud, but a little different from other GBBRs in that it's oddly similar to a branch breaking. Recoil is very satisfying as the bolt is heavy and traveling at full stroke so it gets a lot of momentum. Because of this, firing in semi-auto accurately needs a bit of practice and I find shooting it in the prescribed old school method (bladed stance, chicken wing) works best. The hop adjustment dial can be a bit loose however and may require tightening using tape or a thin layer of super glue to keep it from walking out of setting. Also because of the massive bolt, gas consumption and cool down are against it. With moderately paced semi-auto fire, a fully gassed 50 round magazine will shoot enough for 70-80 bbs worth which may seem a lot but it holds a lot of gas to begin with and even just going through 50 rounds it already gets very cold.


Now, with the basic information done, and having had this for a couple months and working on other units even earlier than I bought mine, below will cover a list of manufacturing problems, as one would expect from WE, and how to address them.

Barrel wobble

The barrel and receiver assembly does not copy TM's AEG design but of Hudson's PFC design which is very close to real steel. The handguard metal is screwed to the barrel and both are socketed into the receiver and a screw at the bottom goes through all three pieces sandwiching them together. This is a very solid design, however WE has some production issues such that the screw installed is way too short. It only really engages the barrel by two turns and it doesn't take a lot of rounds for the threads to get mangled and the assembly starts to wobble. To fix this, it's highly recommended to replace the screw with a longer one right out of the box: flat head, socketed, M5x18mm. For an even tighter barrel to receiver fit, you can glue a strip of aluminum to the receiver acting as a shim much like how you would address barrel wobble on the WE G36 (G39). I used aluminum from a soda can and folded it over making it 0.3mm thick and about 20mm wide long enough to make a letter "C" around barrel.



Nozzle breakage

Some units have experience having their nozzle break in two and I found it to be the cause of a short and loose pin. The front and rear section of the nozzle is connected by a pin which, again, with production issues is shorter than it should be. The pin walks out from recoil and because it's short, one side eventually becomes unsupported and the protruding part of the pin hits an area on the receiver which eventually breaks the nozzle. A good solution is to replace the pin altogether with one that covers the full width of the nozzle and preferably from high carbon spring steel. If you can't find/make a pin, you could also just super glue the original pin in place so it doesn't walk out. Also be observant of the pin every so often, checking to see if it's walking out.


Bolt wear

Even with just a couple mags through, many have complained about excessive bolt wear on its underside. You can clearly see the scratch marks and in the worst cases the lower receiver is littered with metal shavings. The cause of this, ironically, are the steel reinforcing inserts WE put on the sear. The edges of the inserts are very sharp and work the bolt like a chisel. To fix this you simply have to dull the edges of the inserts with fine grit sandpaper (800 and up).

Bolt wear shown only after a few mags for testing, but has not progressed after seeing 1.5-2k rounds after being fixed


Dulled edges of sear inserts. You can barely see the difference but I put roughly a 0.12mm radius on the edges.



Receiver wobble

While this isn't much of a problem on its own, many have complained about it so I've devised an easy way to address it. Using a wide rounded punch, I hammered a dimple into the upper receiver rails near the opposite ends so that the displaced metal creates a hump. This acts as a spacer to tighten the engagement between lower and upper receiver. You don't have to hit too hard, just repeated light taps will do until the desired tightness is met. Shown are one set of dimples on each side but I later added an extra set of dimples next to the first ones.




Double feed

This problem doesn't happen very often but is a pain when it does as the extra bb doesn't always go down the chamber and instead lodges itself between the bolt and barrel causing a jam. I've rooted the problem down to fairly loose feed lips and to fix them I simply heated the feed lips and clamped them to the right width until cool. I used a heat gun, making sure to rotate the mag constantly to heat the lips evenly. When you see the edges of the plastic begin to get shiny, that's hot enough. I then clamped the lips down with a vise grip pre-measured at 12mm and blew on it until it cooled down.



Edited by renegadecow
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