This time, we'll be disassembling the Baton BG-17 CO2 GBB (Glock 17 GEN.5) first production run that I introduced previously.
As of the time of writing (February 4, 2023), there seem to be a few minor issues, so I will proceed while checking each component from the perspective of a former engine designer.
I'll proceed while also considering the direction of customization. The product I'm disassembling this time has been used by me for test firing, approximately 300 rounds.
*This article aims to provide educational explanations from a mechanical engineering perspective regarding the safe hobby use of airsoft guns.
This does not promote acts of violence, the use of weapons, weapon modification, practical evaluation, or violation of laws and regulations.
Disassembling the slide
Let's do a field strip on the slide.
Cock the slide, then press down the takedown lever shown in the picture.
The slide is removable.
Let's look at the contents of the slides.
リコイルスプリング
Let's take a look at the recoil spring.
It features a double spring, just like the real thing. It also has a resin and rubber shock buffer.
When a spring is doubled like this, it becomes an uneven spring constant spring, where the load constantly changes with respect to displacement. The advantages are that the load is simply larger with two springs, and because of the uneven spring constant, it is less likely to resonate when the spring moves at high speed (resonance causes sounds like "boing").
This is a common technique used in engines; for ultra-high-revving engines (for example, those with a rev cut-off at 15000 rpm), they might use double valve springs with unequal pitch.
However, the puzzling thing is that in modern times, with advanced technology, it's possible to use a single spring with unequal pitch winding, and it's a mystery why they would even use it in a handgun, which has a slow rate of fire (double springs in car engine valves have also drastically decreased).
Next is the operating status.
When you press it down with your hand, it feels like it's under quite a strong load.
As of this writing, it appears that some users have experienced a break in the spring guide (the core part of the spring made of resin) of their recoil spring.
My personal theory is that the MOS slide was designed with a higher spring load to maintain operation when a heavy red dot sight was mounted on the slide, but I suspect that this backfired and caused it to break.
If the spring is not assembled straight, it will move in a meandering motion rather than a straight line when it expands and contracts (spring oscillation). This meandering motion becomes a lateral load (thrust load) on the guide, which can lead to failure (guides are generally assumed not to be subjected to thrust loads).
One possible cause is that the springs weren't assembled in the correct straight shape (which is obvious, but difficult in mass production).
As a similar example of a problem, if the valve springs in a car engine are not assembled straight, the engine will crash immediately. Therefore, the geometric tolerances, such as the flatness and perpendicularity of the spring seat, are strictly controlled (springs are a complex subject).
At this point, the only solutions would be to either replace the spring with one that has a lower load capacity, or to carefully assemble the spring so that it is straight (even just carefully assembling it would be quite effective).
This particular part is often removed casually during field stripping, so paying a little extra care during assembly will make a big difference (I recommend checking that it's assembled straight).
Furthermore, while the MOS is a great system, mounting a heavy red dot sight will increase the load on the spring, so it's better to choose a lighter red dot sight.
In any case, I think it's a place where countermeasures will likely be taken in the near future.
My approach will be to carefully reassemble it so that it is straight, without changing the spring.
Barrel area
Next, let's look at the outer barrel.
It was metal (cast aluminum).
Since it has a metal outer barrel, it has the usual safety hole on the bottom.
It appears that this outer barrel is also being worn down, but this may be unavoidable as aluminum castings have a very low hardness (around HB100) (even T-6 and T-7 treatments don't make them much harder).
Wrought alloy (AXXXX, also known as duralumin) would be ideal, but the cost would increase considerably, so I suppose it can't be helped.
Next, we will remove the chamber.
Remove the chamber from the outer barrel (this requires a fair amount of force).
This is the removed chamber (the screws have already been removed).
We will now open the chamber.
The hop-up adjustment mechanism was quite simple and classic.
Let's take a look at each part inside the chamber.
This is a hop-up arm.
正面です。
The arm and shape are the same as the BM-45 from the same company that I introduced previously, but the angle of the push-in part is quite different.
I think this is because the hop-up packing was changed from TK-WF in the BM-45 3rd lot to BN packing in the BG-17.
This part is not compatible, so if you change to a TK-WF packing, you will also need the hop-up arm as a set. The same applies in reverse.
Next is the hop packing (BN packing).
I think the blue color is for identification purposes.
This is the convex shape of a hop.
The TK-WF packing, which was often used by Baton, had a long, two-pronged shape and was quite elaborate, but the BN packing had a simpler knob shape.
Personally, I prefer a longer hop-up arm, but the shape of the hop-up arm is not suitable for that, so I think they changed it to a simpler, knob-like shape.
Next is the inner barrel.
Hop window section.
The material is aluminum pipe (drawn or extruded), and the shape of the hop-up window has many right angles and seems to have a lot of machining burrs, so I didn't really like it (the BM-45 is the same). Therefore, I'm going to change the inner barrel to an aftermarket one.
tip.
The tip is a simple tube with no tapering or other processing.
The inner barrel specifications, as measured, are 6.05mm in diameter and 97mm in length, which is a standard size for Glocks, so there should be many compatible parts available.
Blowback engine
Next, we will remove the blowback engine.
First, remove the MOS cover at the top of the slide.
Removing the cover reveals the nozzle return spring.
Remove the spring carefully, making sure not to let it fly off.
Next, remove the screws that secure the breech.
Now you can remove the bleach. The extractor will also come off at this time, so be careful not to lose it.
Now let's look at each part.
Breach and piston cup.
The piston cup was trapezoidal rather than circular due to height limitations imposed by the MOS (same as LAYLAX's M17).
The piston cup's surface area is approximately 122.8 mm² when converted to a trapezoid, which is equivalent to a diameter of φ12.5-13 mm on a circular surface. While this is not as large as the recently popular φ15 mm, this model uses carbon dioxide to create high pressure, so a slightly smaller surface area should not be a problem.
The Baton BM-45 featured in this blog had a φ14mm diameter, so the recoil felt stronger in comparison (although other factors such as slide weight also play a role).
It seems like this part was designed with MOS in mind.
Next, let's look at the bleach from above.
It's on the bottom.
The breech appears to be made of cast aluminum (I don't think it's zinc based on its specific gravity). Due to the limited space for the MOS, some parts are thin, but the part that the hammer hits has a thickness of 2.6mm, so I don't think it will break easily.
However, since it's made of soft cast aluminum (I think the hardness is around HB100), the parts that come into contact with the hard iron parts of the hammer will wear down. However, this wear is common in gas blowback guns, not just this model, so I think the durability of the breech is average.
Next, let's look at the nozzle.
Regarding the nozzle, it seems they've made some ingenious efforts to compensate for the limited vertical space due to the adoption of MOS technology.
What's particularly concerning is the low height of the tappet section, which is responsible for feeding the ammunition. However, since the tappet's function is to push out the BBs, the load on the material is mainly compressive stress, so I think its durability will be fine. However, if lateral loads are applied due to incorrect assembly, etc., it is weaker than conventional gas blowback guns, so it's a part that requires careful handling.
Let's take a look at the nozzle from the back.
The flow valve appears to be secured with a pin.
We'll start by removing the pins to disassemble the nozzle.
Signet Pin Punch Set
It's not a luxury brand, but it's a recommended mid-range brand in the automotive industry that offers good value for money. Plus, it's inexpensive.
Eagle Force Maintenance Bench Block for Handguns
It's incredibly convenient to have. Moreover, it's designed for handguns but can also handle longer firearms, making it very useful. In fact, I personally didn't see the need for their M4 version.
When you remove the pin, the flow valve will appear.
The flow valve now features the popular anti-rotation mechanism. However, one slight concern is that, for a carbonated beverage model, the flow valve spring is quite long and the load is rather strong.
I was surprised because carbon dioxide gas has a high pressure and therefore a higher initial velocity, so it generally uses soft and short springs.
This completes the disassembly of the blowback engine.
Finally, here is an overview of the blowback engine components.
slide
Finally, let's look at the slides for Dongara.
The slide is made of nylon resin, as is typical for Baton's products, so it seems quite sturdy.
We'll take a close look at the areas where the slide might break.
First, the breech insertion area (the back of the serrations at the rear of the slide)
It seems that Mr. Baton's experience is coming into play here, as he's carefully added material to increase the strength, so it should be fine.
Next is the casing ejection port.
There's plenty of meat, so it should be fine.
Finally, the tip of the slide (the back of the serrations at the front of the slide)
The meat is generally well-filled and seems fine, but the areas where the mold's cut surfaces meet might be slightly weaker.
If this slide is damaged, it will look like the following picture.
However, this is merely a prediction in case it breaks, and it doesn't mean this slide is weak. On the contrary, it seems to incorporate quite a few countermeasures based on past experience.
This completes the disassembly of the slide.
Summary
My impression after disassembling the slides is that, despite struggling with MOS (Motion Sensor), they managed to put it all together quite well through ingenuity.
It appears that adopting MOS (Motor System) significantly restricts the height of the blowback engine space, which seems to have presented some challenges.
While the design is generally high-level, there are two points that personally bothered me.
- The recoil spring is strong → There's a possibility that the spring guide is damaged.
- Some parts of the breech are thin → may crack if unintended load is applied.
All of these aspects stem from the adoption of unprecedented MOS technology, making them challenging areas where past data cannot be used. It's difficult to predict the outcome, but I was curious to see what would happen (the parts other than MOS are quite well-developed).
Also, this is the part of the MOS that will experience a significant increase in load if a heavy red dot sight is mounted on it, so it's best to be careful.
Taking the above issues into consideration, I would like to proceed with the customization in the following direction.
- Replace the inner barrel (with one that has a clean hop-up window).
- Reassembling the recoil spring, cutting the spring, or replacing the spring
- Polishing and greasing of each sliding part
That concludes the disassembly of the slide.
Next time, we'll take a look at the chassis section by disassembling it.
If you're interested, please check out my explanation of the gas blowback mechanism.
Baton BG-17 CO2 GBB (Glock 17 GEN.5 MOS)
If you buy it online, it's hard to tell before and after the hammer incident. With Amazon, you'll be taken directly to Baton, so you might want to contact them and confirm.
Baton BG-17 Spare Magazine
This magazine seemed like it would be quite durable.
・Baton (PUFF DINO) CO2 12g cartridge
These are genuine gas canisters. The manufacturer is Puff Dino, but Baton is the authorized distributor and treats them as genuine. It seems that only these canisters are eligible for the 3-month warranty. You can choose between packs of 6 or 50.
Marushin CO2 12g cartridge
I think Marushin offers the best balance of price and quality. You can choose between a set of 5 or 30. However, you will no longer be eligible for Baton's 3-month warranty.
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