Bolster Tuned CYMA CM.041 SMG-5 Upgraded AEG

The Original CYMA CM.041 Platinum Edition

The basis for this upgraded AEG is the superb CYMA CM.041 SMG-5. When the Bolster Armouries team first got their hands on these they were very impressed with the quality of their internal parts, seeing great potential in the platform for some fine tuning and a few small parts changes. What the Bolster Armouries techs produced is absolutely exceptional, and refines the mass-produced CM.041 to perform at the absolute pinnacle of its capability.

On the outside, the CM.041 is dressed to impress with its slick modern M-LOK handguard and M-LOK/Picatinny hybrid upper rail and looks fantastic with its AR buffer tube and compact crane style stock. Nothing really needed changing on the outside, thanks to the rock-solid full metal construction of the CYMA and its cutting-edge design attributes.

If you want to join us as we discuss the externals, read on, but if you are more interested in what Bolster Armouries have done on the inside of these bad boys, you can skip to the next section!

At the tip of the barrel, we have an SMG-5 QD flash hider, which can be quickly removed to provide access to the threaded tri-lug muzzle device beneath. On the left side we also find our first sling point, which is integral to the front sight block and is perfect for hook-style two-point or three-point slings.

To remove the flash hider, all you need to do is press the textured tab on its outer rim, and the flash hider should come straight off. The barrel threading is protected by a knurled thread protector, and you will be happy to learn it is threaded to the most common Airsoft standard; 14mm CCW male threads. This means adding a tracer unit or suppressor is no problem if you want a sneaky look or some extra intimidation factor for CQB.

Moving rearwards we come to the front sight, which is a classic SMG-5 design with a fixed front post protected from drops with a protective ring which surrounds the sight post. This sight aligns well with the rear rotary drum dioptre aperture sight, found on the rear of the receiver, and is widely known as a fantastic built-in sight system, though with its M-LOK/Picatinny hybrid upper rail, this SMG-5 would benefit a lot from adding a red dot sight for faster aiming.

The rear sight provides four apertures for aiming, intended for different ranges and ambient lighting conditions, which can easily be switched between thanks to its knurled outer surface. To adjust the rear sight for windage you can loosen the screw in the base on the right side and slide the rear sight back and forth in its base.

Following the front sight we come to the handguard of the CM.041 which boasts M-LOK attachment slots at the 3, 6, and 9 o'clock positions, with an SMG-5K style vertical grip/hand stop pre-installed at the 6 o'clock position. We love this grip, and it does all it needs to, but if you want to swap it out, you can thanks to the M-LOK attachment interface. M-LOK can be used to mount tactical flashlights, vertical and angled grips and also 20mm Picatinny rail adapters in case you want to use the older but more common 20mm accessories.

Above the handguard, we come to the cocking tube of the CM.041 which is constructed from robust alloy with a lovely flat black finish applied. Within you will find the cocking handle, which is a modernised design which is optimised for gloved use and profiled as such that it is slightly easier to access from the left side. Pulling the cocking handle rearwards allows it to be locked into its "safety notch", which will open the ejection port on the right side of the receiver to allow for HOP-up adjustment.

Running along the top of the cocking tube and receiver we have a hybrid M-LOK/Picatinny top rail which allows for M-LOK attachment at the front and provides a 20mm Picatinny rail at the rear. This rail is perfect for adding an M-LOK mounted tactical flashlight up front and a red dot sight on the 20mm rail. Innovations like this allow compact weapons like the SMG-5 to keep up with longer weapons like the M4, providing plenty of room for the mission essential kit we all love to dress our primaries up with. Now your SMG-5 can look as slick and battle-ready as your MK18!

The receiver follows the familiar SMG-5 format but with some choice enhancements to help this 60s era SMG turn and burn in CQB with the more modern stuff. The magazine release is ambidextrous and is located at the rear of the magazine well with an additional polymer extension added to allow for one-handed mag drops. The fire selector is ambidextrous, located just above the pistol grip for fast access.

The super short 45-degree throw between selector modes makes this SMG-5 extremely fast and easy to switch from safe to fire, and the selector is positioned so the opposite side selector does not dig into your hand when the SMG is set to full auto. Each fire mode is indicated with red and white coloured bullet pictograms, in iconic SMG-5 style. The trigger of the CM.041 is another feature which departs from the SMG-5 norm, being a flat trigger design to allow for super fast semi-auto fire, with a small ledge at the bottom to keep your trigger finger where it needs to be.

Either side of the receiver features grooves which both serve to reinforce it and to allow for the SMG-5 sliding stock to travel within. The CM.041 uses a more modern stock setup, but these grooves are none the less necessary for a realistic SMG-5 look. The ejection port is located on the right side of the receiver and provides access to the HOP-up unit when the charging handle is locked to the rear.

The HOP-up unit of the CM.041 has been considerably refined by the Bolster team, but we will discuss that in the next section. The HOP-up design is a rotary style unit, the more modern HOP-up style for the SMG-5, and allows you to tune the level of backspin applied to your BBs and extend the range of the AEG. Applying HOP-up also allows for ammo of heavier weights to be used for outdoors skirmishes, allowing this little SMG to duke it out with the big boys in the woods when needed!

At the rear of the CM.041, we find a unique stock setup. Unique, at least, for an SMG-5! The use of more advanced stock solutions gives you one less part to source and buy if you want a 21st-century approved SMG setup, and offers some superb functionality that the legacy SMG-5 stocks simply cannot provide. 

The CM.041H provides an M4/AR15 style 5-position buffer tube, and a compact crane-style stock with QD sling points on either side, which is easily adjusted, and well suited to the compact form of the SMG and its role on the battlefield. The adjustment lever is located on the bottom of the stock and has helpful gripping texture on its surface to make it easy to use regardless of any wet weather. The rear plate also features a sling point which is ideally located for a single-point sling.

The battery compartment of the CM.041H is inside the buffer tube and can be accessed by removing the stock by lifting the adjustment lever out and sliding the stock off the tube to the rear. Given the internal refinements present in this SMG-5, we recommend an 11.1V 1300mAh LiPo buffer tube style stick battery to give it the oomph it needs to perform at its best!

The CM.041G variant uses a PDW style stock, giving it a different look and making it that bit more compact. The adjustment lever for this stock is on the left side and is easy to reach with the thumb when in a firing grip. The PDW stocked variant will require a smaller battery than the M4 stocked model, so we recommend an 11.1V 600mAh PDW type stick battery for easy fitment and great performance down range. Both of our upgraded CM.041 variants use a Deans battery connector, allowing for reduced resistance and superb electrical efficiency. 

The choice of adjustable stocks allows the CM.041 to be adjusted to suit any body type or loadout, and for CQB, both of these setups are amazing when used in their fully collapsed position. 

Now, let's get on to the good stuff, and check out what the Bolster techs have been doing inside the CM.041!

The CM.041 Patrol Base X Gate ASTER Edition

This isn't your usual "upgraded" AEG, where you pay for the parts and labour and the tech does only what they are paid to do. The Bolster Armouries tech team fully disassemble each of these AEGs down to every screw, bolt and bushing to perfectly tune the internals, polish the piston tracks and bearing holes, shim the gears to absolute perfection and replace parts to address the weak points in the original CM.041. The Bolster techs treat these AEGs like they are building them for themselves, and if it doesn't pass their rigorous checks, which include a 60m accuracy test, it goes back to the bench for more work.

To replace the original CYMA ETU, the team have added the exceptional Gate ASTER ETU/MOSFET to add some seriously advanced features to the CM.041 and kit it out to contend with the best. The ASTER boasts programmable fire controls through the Gate Control Station app, Gate Blu-Link or Gate USB Link, adjustable pre-cocking for a ferocious trigger response in semi-auto, cycle timing control, adaptive active braking, adjustable trigger sensitivity, and voltage control, all of which combine to give this SMG-5 a wealth of functionality that is hard to beat.

Installing the ASTER requires modification of the gearbox shell and selector plate for compatibility with the ASTER's optical sensors. Copper is no longer used on the selector plate, and is instead replaced with an ASTER sticker to allow the optical sensors to detect its position, and adjust the fire mode accordingly. This has the benefit of being more reliable than a traditional selector plate, as the use of optical sensors takes corrosion which usually develops on electrical contacts out of the equation completely.

As you will receive it, the SMG is set up for pre-cocking in semi-automatic for a GBB-like instant response, and standard cycling in full auto so you can release the piston and prolong the life of the spring. These settings can be altered to your heart's desire using the Gate Control Station app, or a Gate Programming card, but there is no need to change settings as this AEG is set up to perform exactly as it should, and if there was a better combination of settings, the Bolster Armouries team would have used them.

Inside the gearbox, the Bolster boys have put in some serious elbow grease, and have modified the shell to accept the ASTER ETU, sanded the piston tracks and bushing holes completely smooth to reduce every bit of friction possible, and shimmed the gears to perfection for absolutely flawless functionality. The cylinder window corners have also been radiused, to get ahead of a known version 2 gearbox failure point by more effectively distributing the mechanical stress on the gearbox front from repeated impacts.

The only part they replaced inside the gearbox other than the ETU is the air nozzle, which has been replaced with the Lonex air seal nozzle, complete with an air seal enhancing O-ring. The result is a system which is running at the absolute peak of efficiency, both electrically and mechanically.

Speaking of grease, all of the internal parts of this CM.041 have been treated to Waldo Customs' delicious smelling silicone lubricant, both the THICC and SLIM variety. Waldo THICC lube has been applied to the cylinder head, and SLIM has been applied to the O-rings of the Lonex air seal nozzle and the piston head to prolong their life, enhance air seal qualities, and make them smell great!

One of the biggest issues with mass-produced AEGs is the poor quality lubricant applied from the factory, in inconsistent amounts and in all the wrong places. Bolster Armouries has cleaned up inside the gearbox, and doing this alone makes all the difference. Coupled with the internal enhancements, this SMG-5 sounds more like an A-10 Warthog when it fires than an Airsoft AEG!

When it comes to the HOP-up and inner barrel, the Bolster techs have worked wonders. One of the few complaints we have heard about the original CM.041 is that when fired in full auto extensively, the HOP-up unit tends to lose its setting and require readjustment.

To correct this, the Bolster techs have tightened everything up and replaced the polymer pin holding the unit together with a machine screw and bolt to ensure it remains rigid and effective. Naturally, these guys cannot touch an AEG without installing the phenomenal Prometheus Purple HOP-up bucking and nub inside, and of course, this CM.041 is no exception. This is what allows this upgraded version to nearly double the original in range, reaching out to an absurdly long distance for such a short-barrelled AEG.

The CM.041 comes with a 6.03mm tight-bore inner barrel pre-installed, but not being the types to trust Chinese quality control, the Bolster techs inspect every barrel for imperfections and give them a thorough clean and polish before reinstalling them. Even tight-bore barrels can have internal flaws which effect accuracy when mass produced, and the internal overhaul given to this CM.041 guarantees that you will get a good, smooth barrel with a flawless inner surface.

From a performance standpoint, this AEG is positively exceptional, being accurate to 60m and beyond, and ripping out BBs at a nauseating rate (for the other team, anyway!). When put on the chronograph this upgraded CM.041 spits out an incredible 25 BBs per second, which isn't far off the proper Bolster Armouries ONYX AEGs. FPS-wise, this AEG hits a very consistent 330 FPS when tested on 0.2g ASG Blaster BBs, but the Bolster Team recommend 0.28g BBs to make the most of the Prometheus HOP-up rubber. If you ever wanted an ONYX but cannot stomach the price, this is the next best thing!

The CM.041 Patrol Base X Gate ASTER Edition benefits from the same decades of experience and careful hand-building process that the ONYX does, but takes advantage of the impressive stock parts in the CM.041 instead of replacing it all with aftermarket upgrades. It's amazing what talented technicians can do with a mass-produced AEG and a few choice upgrades, some great quality lubricant, and a world-beating ETU like the ASTER.

Package Includes

• CYMA CM.041 SMG-5 Patrol Base X Gate ASTER Upgraded Edition
• 3x 130rnd Mid-cap Magazines