Contact Us Tel:(626) 286-0360 Store Locations
Phone Support M-F 9am-5pm PST
Browse by Type or Category
FREE SHIPPING for orders over $99! New deals released hourly and daily. See Deals Here!

EMG x Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series Airsoft AEG Rifles (Color: EMG Blue)

ID: 18709 (GB-EMGxRA-CNCV2-BU)
6392 CNC Gearbox Ver. II 8mm - EMG - BLUE
EMG8591881870926392 CNC Gearbox Ver. II 8mm - EMG - BLUE18709
4.3 stars, based on 3 reviews
EMG x Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series Airsoft AEG Rifles (Color: EMG Blue)
Hover or touch above to zoom
Youtube preview Product image 1 Product image 2 Product image 3 Product image 4 Product image 5
EMGRetro ArmsEvike Exclusive


MAP ProtectedExempt From Coupons
The manufacturer of this product enforces a strict minimum advertised price (MAP) policy which excludes this product from any additional discount coupon codes. This item, however, may qualify for free shipping.
Free ShippingNo Coupon Required
Free shipping within lower 48 US states, no coupon code needed!
Color Options:


  • Precision machined from a block of billet EN AW 7075 T651 aluminum
  • Quick change spring guide system
  • Durable anodized finish
  • Reinforcement in key stress points to counter rapid wear from high performance parts
  • Pre-radiused cylinder windows - helps evenly distribute impact force
  • Deeper wire channels along base of gearbox
  • EMG Logo engraved on side of gearbox
Unlike most other gearbox shells on the market, the Retro Arms CZ gearbox shells are precision CNC machined out of a solid block of billet EN AW 7075 T651 aluminum giving them unmatched durability and resilience. Combined with reinforcement of key stress points and stainless steel connecting bolts, the gearbox shell has undergone extensive stress tests with M160 springs without any signs of wear.

Version 2 Retro Arms gearboxes feature a quick-change ball-bearing spring guide mechanism, allowing spring swaps in a matter of minutes without complete gearbox disassembly.

Manufacturer: EMG x Retro Arms CZ

Color: EMG Blue


Compatibility: For Tokyo Marui, G&P, Matrix and other compatible M4 / M16 Series Airsoft AEG Rifles (Modification may be required depending on brand and model)
Material: CNC Billet EN AW 7075 T651 Aluminum

Disclaimer: Please use discretion when installing custom parts as fit and compatibility may vary. Some modification may be required. Professional installation recommended.

About EMG

The EMG vision is to manufacture products the world has never seen before; products we would put our name on, and products that hit the spot! "EMG" (Evike Manufacturing Group) was spawned from the realization that if you want something done exactly the way you want it, you need to do it yourself, and we did just that.
We took our 16 years of knowledge as the market's lead retailer, our network of 300+ superior manufacturers, to work with inspiring top innovators in the firearms industry. That combined with the vision to invest into the Airsoft industry, an industry we believe in, EMG was born.

About Evike Exclusive

At, we believe that superior outdoor recreational products can create a better world. That is why we develop, innovate, and pioneer to bring you the perfect experience, service, and products.

3 Customer Reviews

(Write a review)

by Jordan C. on 05/15/2021
"Put this in my limited edition vfc m27 with a retro arms j trigger in the matching blue color and it's beautiful. Had my freind who owns a pro shop build it with siegetek gears and a gate titan. Yes go retro arms for a fully built aeg and a great conversation peace ✌
by Will P. on 03/02/2021
"We installed one of these for a customer, I agree with the first review, and I have to add, if somebody out there is planning to install a Gate Astor, plan to paint the inside of the box flat black. not a big deal, but its soo shiny inside that the single sided boards get all screwy with the light bouncing around. Really should use a Titan or similar, but our customer provided the parts.
by Gavin N. on 02/08/2021
"I have this in my VFC mp5, no fitment issues.

We all know how great and strong these gearboxes are so here are some things to note that aren’t as great.

- Was expecting it to come in a box, instead came in a clear plastic bag, kinda lame but didn’t affect the durability on mine
- The holes for the bushings are too small, I tried FLT, Modify, and even Retro Arms but none fit, I had to open the holes up for any to fit
- The screw used to mount the trigger contacts/board isn’t the same size as most gearboxes. Not a huge deal but why?
- The qc spring guide is nice, but the torx head on the back is wayyyy too big, retro arms even sell a screw-in knob for the guide. Again, why?

Comments & Community

Discuss about EMG x Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series Airsoft AEG Rifles (Color: EMG Blue) with your friends and fellow shoppers!

Have an urgent question about this item? Contact us, our resident experts are standing by to answer your questions!

California Proposition 65 Warning: Cancer and Reproductive Harm -

Customers who bought this also purchased

Parts and accessories may not be compatible with the product displayed on this page. For compatible parts/accessories, see the You May Also Need section and please verify details on the product description page.