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General Information

UPDATED ON 2-25-16... Added pictures, Field-tested it, added a GATE MOSFET, replaced the wiring and am using an11.1 lipo...

UPDATED ON 12-5-15... Added Internal before and after pictures, flat-hopped it, listed internal pieces, and updated the description, etc...

I was interested to get an AK variant AEG at some point and have done so with this gun. I wanted to keep everything as cheap as possible in case I did not like the feel, gearbox, or size of an AK, Which is why I purchased the CM.028-S Model. After using it for awhile, I have taken a liking to it and will eventually be getting a higher end AK model in the future.

(UPDATES-[AS OF 2-25-16]) As you will have noticed in the pictures, I have given this AK a weathered look as best as I can and have installed a few basic upgrades. As far as the upgrades go, I have attempted to Flat-Hop it, Tuned the Hop-Up, (Thank You Tackett for the Stickied Thread on Fine Tuning a Hop-Up.), Added Deans Plugs, got an11.1 lipo, replaced the wiring, added a GATE MOSFET, Replaced some of the plastic internal pieces that seemed weak (see next paragraph), Added a stronger spring, Corrected the AOE, Re-Shimmed And Re-Greased it. (See the last two pictures for a before and after of the gearbox.)


As far as what I have done inside the gearbox, I will list the parts that I have used:

SHS Full Steel Tooth Piston -

SHS Piston Head (The stock CYMA piston head was worthless in my opinion as far as air compression goes) -

LT Air nozzle -

Matrix Metal Spring Guide -

Matrix Tappet Plate -

Matrix Metal Cylinder Head (Again, The stock CYMA cylinder head Bellowed for air loss) -

SHS M110 Spring -


Shim Set (I was not expecting the shimming to be perfect obviously, but I have read that the shimming on stock Cyma\'s was iffy/good, but this was one of the Worst shim jobs that I have ever seen on a stock airsoft gun.) -

I used Super Lube to Re-Grease the gears. -

The Angle Of Engagement was corrected with One Faucet washer and a small amount of Sorbothane using locktite superglue. -


As far as Outside of the gearbox goes, here is a List of other parts and the battery:

11.1 Lipo -

Battery Bag -

Hop-Up Bucking (I will be getting a G&G green bucking soon as I\'ve heard that they are the best to Flat-Hop with) -

The Nub I used inside the Hop-up was made and cut out of a pink eraser... -

I currently use King Arms 120rnd Mid-cap Magazines and have had good luck with them -


With doing what I have done, I was chronoing near a consistent 350 FPS with .20g bb\'s and am getting an effective range of 175+ft and able to hit targets at 200ft when using .28g bb\'s on the field.

One small plastic piece that was used to adjust the slider on the Hop-Up shattered after adjusting the Hop-Up a few times. However, I made a small metal piece from a chain that works a lot better and feels much more sturdy. The fifth from last picture shows the small metal piece that I made from the chain seated in the sliding part of the Hop-Up. At some point, I might make a quick guide on how I did this in case other people have the same problem and don\'t want to pay $20 for a new metal Hop-Up...

Thank you for reading,



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