In the previous article, we completed the frame of the Baton BG-17 CO2 GBB (Glock 17 GEN.5) custom build, part 1.

This custom build will address the remaining challenges.

I'll proceed with customizing the slide and magazine.

Slide assembly, custom

First, we'll customize the blowback unit.

Customization of blowback units

Let's take a look at the components of the blowback unit.

We will now proceed with the bleaching process (polishing).

When machining (polishing) the breech, remove it to prevent metal shavings from getting on the piston.

Next, let's look at the area to be polished.

Basically, the areas to be polished are those that come into contact with other parts.

The polishing method is the same as usual: rough processing with a rotary tool's grinding wheel, followed by finishing with a buffing wheel.

grinding wheel for rough machining

Finishing buff

Dremel High-Speed ​​Rotary 4000
This is my go-to rotary tool that I always use. Having this expands the possibilities of your DIY projects. There are two popular models, the 3000 and the 4000, but I recommend the 4000 because it comes with a set of tools and has more power.

This is a photo after bleaching.

The bleaching process is now complete.

Next, we'll customize the nozzle.

This nozzle will be used to implement measures to increase and stabilize the initial velocity in custom challenges.

This product has significant vertical play in the magazine, causing variations in muzzle velocity depending on the magazine's position. One possible cause is that the seal between the magazine's gas route packing and the nozzle's gas route is not tight enough (resulting in gas leakage).

One way to address this is to adjust the magazine's position so that it is raised higher. However, raising the magazine's position may cause the gas route packing and nozzle to interfere with each other and become damaged.

Magazine inserted (normal state)

Magazine inserted, pushed up.

Therefore, lifting the magazine carelessly carries the risk of damage, so the issue of gas route tightness will be addressed not by adjusting the magazine position, but by modifying the gas route of the nozzle.

I attached a 0.2mm plastic sheet to the gas route section of the nozzle. The reason for using 0.2mm is that the recess in the gas route section of the nozzle was 0.2mm, so I decided to fill it in.

Tamiya Plastic Sheet 0.2mm
The plastic sheets I often use are from Tamiya, a brand I trust, rely on, and that offers consistent quality.

Loctite adhesive with brush
I use the reliable Loctite adhesive with a convenient brush applicator.

In this state, the gas route of the nozzle remains blocked, so we attach a ball end mill to the rotary tool and carefully machine it to restore the original hole shape.

Ball end mill (included with the Dremel rotary tool mentioned above)

This is a nozzle after processing is complete.

This should improve the tightness of the gas route.

Next, I install the flow valve into the nozzle. When installing the flow valve, I apply Bellhammer Gold Grease No. 0 inside the nozzle to ensure smooth movement.

(The photo doesn't show a plastic plate attached to the gas route of the nozzle, but it is attached in the custom-finished version.)

Bellhammer No. 0 Gold Grease
This is a classic, top-quality grease. No. 0 is a low-viscosity grease. I generally use No. 0 for resin-to-resistance and resin-to-metal connections.

Next, we'll assemble the nozzle into the bleach.

Before assembly, apply No. 0 grease to the area where the breech and nozzle will come into contact.

After assembling the nozzle into the breech, apply No. 0 grease to the top surface of the nozzle as well (so the nozzle and slide can move smoothly).

Before installing the assembled blowback unit into the slide, apply No. 0 grease to the nozzle sliding surface of the slide.

Before assembling the blowback unit, we'll install the extractor, which is often overlooked.

Next, assemble the blowback unit and tighten the screws to secure it.

(The photo doesn't show a plastic plate attached to the gas route of the nozzle, but it is attached in the custom-finished version.)

If the screws are overtightened or misaligned, the nozzle will not move smoothly, so assemble the nozzle while checking its movement.

The blowback unit is complete once you assemble the remaining nozzle return spring and MOS cover.

Custom barrel and hop-up chamber

Next, we'll assemble the barrel assembly.

Regarding the barrel, I don't like the shape of the stock hop-up window, so I'll be replacing it with an aftermarket one.

I originally wanted to use a barrel from Maple Leaf, but I couldn't find a 97mm barrel in stock for the Glock 17, so I chose the KM Planning TN inner barrel this time (personally speaking, I think the barrel alone doesn't contribute much to the performance, and what's important is the shape of the hop-up window).

The reason is simply that I like the shape of the hop-up window, and the barrel inner diameter is 6.04mm, which is closer in size to the original 6.05mm.

Let's compare the stock barrel with the TNT barrel.

Hop-up window shape comparison (top black is the original, bottom silver is the TN barrel)

The hop-up window shape on the TN barrel looks good, but I prefer Maple Leaf's.

Barrel tip comparison

The barrel tip appears to have a tapered design.

KM Planning TN Barrel, Inner Diameter 6.04mm, Length 97mm (Compatible with Marui P226, G17, and G18C)
This is a domestically produced barrel. It seems to have high precision. It appears to have a unique TN coating, but after researching it, it seems to be a Teflon-based surface treatment, so it is probably hard and smooth.

We will now attach the hop-up packing to this barrel.

Apply silicone grease around the hop-up window of the barrel (make sure to fill the groove for the packing).

AZ Silicone Grease
This is a standard product from AZ. While Tokyo Marui's genuine grease is sufficient, the quantity is small, so AZ is recommended. It's also inexpensive.

Attach the hop-up packing to the barrel and wrap it with one layer of sealing tape to complete the process (improves airtightness).

If you wrap the tape too tightly, it won't fit into the hop-up chamber, so one wrap is probably best.

KAKUDAI Seal Tape
This is a standard item for ensuring airtightness in all kinds of applications and can be used not only with airsoft guns but also with other items.

The barrel is now complete.

Next, we'll work on the hop-up arm.

Similar to the company's BM-45 CO2 GBB that I reviewed previously, I felt that this product also lacked sufficient hop-up, so I will be taking steps to address this.

Hop Arm

To increase the amount of hop-up, you simply need to increase the amount you push it in, so we'll put a cover over the part of the hop-up arm that contacts the hop-up packing.

Normally I would use plastic sheets or something similar, but the contact points on this model are curved, not flat, making it troublesome to use plastic sheets, so I'll use heat shrink tubing instead.

If you use a tube that's too large in diameter, it will be too loose, so I used a tube with a moderately sized inner diameter of 5.2mm.

Once molded, it will look like the following picture.

It's now complete. However, with 0.2g BBs, the hop-up might be too strong even with the hop-up adjustment set to 0 (use 0.25g BBs to compensate).

Next, we'll assemble the hop chamber.

Here, we'll simply assemble it carefully without making any modifications. However, we will apply Bell Hammer Gold Grease No. 2 to improve the operation of the hop-up dial.

Bellhammer No. 2 Gold Grease
This is a classic, top-quality grease. No. 2 has the same ingredients as No. 0 but with a higher viscosity. I primarily use it for metal-to-metal connections.

Close the lid on the chamber and tighten the screws to secure it.

This chamber has a part that slides against the outer barrel during short recoil, so apply No. 2 grease to it.

Other side

We will now install this into the outer barrel.

Before assembling the completed outer barrel into the slide, apply grease No. 2 to the parts where the slide and outer barrel slide together.

Assemble the outer barrel and you're done.

リコイルスプリング

Next, let's look at the recoil spring.

Since I didn't take it apart in the disassembly section, I'll disassemble it here.

These are the components of a recoil spring.

It appears that the guide rod of this recoil spring is breaking, so I will consider countermeasures.

A simple solution would be to reduce the load on the recoil spring, which would involve cutting the spring.

The problem with cutting the spring is that it makes it difficult to properly finish the end of the spring and wind the spring coil neatly, and it also reduces the sliding speed, which is a key selling point. Therefore, we decided against cutting the spring.

I tried to think of other methods, but couldn't come up with any, so I decided to carefully assemble it while praying (my brain stopped working).

While applying No. 0 grease, carefully assemble the spring, making sure it doesn't twist (even just eliminating the twist in the spring will have an effect).

Since it's not good for the shock-absorbing buffer to move around unnecessarily, we fix the buffer to the rear end of the guide with a dot of adhesive.

Fixed

Simply put this into a slide and you're done.

Before assembling the slide to the chassis, apply No. 0 grease to the rail section of the frame, the slide's breech, and the barrel.

slide

chassis

The main body is now complete.

Magazine customization

Next, we'll work on the magazine.

The main issue with the magazine is fixing the peeling gas route packing that was visible during the disassembly process.

While examining the peeling, I noticed that the rubber molding of the gas passage in the gas route packing wasn't very good.

If properly molded, the gas route should take on a neat rectangular shape, but the actual product has a distorted, warped shape. With such a distorted shape, the pressure loss is likely to be quite large, resulting in a significant decrease in the product's performance.

Based on my experience, the cause is likely that the rubber curing process (vulcanization, the process of adding sulfur to fix the shape, or more precisely, cross-linking) is not stable (I think even in Taiwan, producing high-quality rubber is still difficult). This vulcanization process is unique to rubber.

The molding processes for metals, resins, etc., which you are all familiar with (the concepts of casting and injection molding), are as follows:

Melt the materials → Pour into a mold → Cool and solidify → Finished

Unlike metal and resin, rubber behaves as follows:

Melt the material → Pour it into the mold →Vulcanization by baking (crosslinking by adding sulfur components to fix the molecular structure)）→Complete

In other words, unlike metals and resins, rubber's shape is fixed by vulcanization (fixing the molecular structure and creating crosslinks with sulfur components) while it is being heated.

This gas route packing probably has a poor shape because the vulcanization process wasn't done very well (the vulcanization process is the most important and technically difficult part of rubber manufacturing).

Let's expand on the topic of gas route packing and discuss the importance and challenges of rubber.

Many of you have probably heard of the hardships the Japanese Empire faced with rubber quality during World War II, as an example of a recent ancestor's struggle with rubber. The specific problem that led to this hardship was a lack of vulcanization technology; Japan had significantly less expertise in vulcanization compared to the Allied powers (you can skip this part if you're not interested).

Humankind's discovery of rubber dates back quite a long time, but natural raw rubber in nature is hard and lacks toughness because its composition is unstable, and it quickly falls apart (similar to a very old, worn-out eraser, where the sulfur has been removed), making it unsuitable for human use. (Even among natural rubber, there are some that happen to have a stable composition, but whether they are usable is a matter of luck.)

Rubber only became industrially usable relatively recently. In the 1850s, an American named Goodyear created the elastic rubber we know today by vulcanizing (adding sulfur) raw rubber (this is actually unrelated to the tire brand Goodyear).

One example that will make you familiar with the vulcanization (sulfur component) of rubber is how tires deteriorate over time, regardless of how often they are used. This deterioration is largely due to the loss of sulfur from the rubber (one of the reasons why rubber has a limited lifespan, regardless of usage).

A little later in that era (1900-1915), automobiles and bicycles became widespread, and a Briton named Dunlop invented the tire by inflating an elastic rubber ring with air (Dunlop is now a tire manufacturer).

This led to an explosive increase in motorization, primarily in the United States and Great Britain (plus France and Germany), and also significantly advanced rubber technology.

Furthermore, rubber is the foundation of all industries, not only for automobile tires but also for fluid seals and electrical wiring insulation (this is still true today; rubber is used extensively in everything from the insulation of everyday USB cables to the cutting-edge H3 rocket).

However, in the pre-war Japanese Empire, civilian-level motorization did not occur (primarily by rail), and rubber was mainly used for military purposes, resulting in limited supply and less competition. Consequently, rubber technology (vulcanization) did not develop to the same extent as in Europe and the United States.

Therefore, it seems that the rubber produced in the Japanese Empire was of poor quality, prone to cracking, hardness, and easily crumbling due to poor vulcanization, and the military was acutely aware of this problem (rubber is essential for all weapons and machinery).

Therefore, the military understood the importance of rubber, and at the start of the Pacific War, they occupied Malaysia and Indonesia (not solely for rubber, but securing rubber was a major reason) almost simultaneously with the surprise attack on Hawaii.

However, even with raw rubber available, the manufacturing techniques for rubber, including vulcanization, remained unchanged, so they struggled to produce decent rubber (it wasn't that they lacked raw materials).

However, at the beginning of the war, it seems they were able to survive by mass-producing even low-quality rubber, thanks to the abundant supply of raw rubber (it was hell for the maintenance workers on the ground).

As the war progressed and the tide turned, the raw material production areas (Malaysia, Indonesia) were seized, and in the later stages, even low-quality rubber could no longer be produced.

In the end, it seems he suffered through the entire ordeal of using a condom.

Germany also had problems with rubber, but unlike Japan, they lacked raw rubber (they had almost no colonies where the raw material could be produced), so they developed synthetic rubber using coal and potatoes, but it couldn't compete with vulcanized raw rubber, so Germany also suffered from rubber problems (for example, from the latter half of Operation Barbarossa, they ran out of rubber for the road wheels of the Panzer III, Panther, and Tiger tanks).

Modern Japan seems to have learned from its mistakes in WWII, and its rubber technology is top-notch (it's overwhelmingly No. 1 in ASEAN, and Japan's chemical industry is incredibly strong in general).

The difficulty of rubber production is not a thing of the past; even today, the situation is similar, and it's not the case that vulcanization can be reliably carried out in every country. It can only be produced in a very limited number of countries.

For example, a leading tire manufacturer, a representative of the rubber industry

Japanese companies such as Bridgestone, Dunlop, and Yokohama.

European brands such as Michelin, Pirelli, and Continental.

American company Goodyear (which was acquired), etc.

They are only found in limited regions, and it's only in the last 15 years or so that brands like South Korea (Hankook) and Taiwan (Nankang) have finally emerged (it's still difficult to call them top-tier).

Recently, semiconductors have been frequently discussed as a strategic material, but in reality, rubber is still a very difficult technology to produce and is a strategic material of equal or even greater importance than semiconductors. Even in Taiwan, which is said to be the world's semiconductor factory, I feel that producing high-quality rubber is still difficult (and in Russia, which is often in the news, producing decent rubber is 99.9% impossible).

In my own experience, even when sourcing and producing engine parts in the ASEAN region, the local manufacturers of rubber parts were not of a usable standard, so it was impossible to do so without having them shipped from Japan or having Japanese manufacturers produce them locally.

During my time as an engine designer, my seniors taught me the importance of rubber, and I also had many challenging experiences with rubber myself, which is why I've written at length about it.

Getting back to the topic, we process the irregularly shaped gas route to correct it into a neat shape (processing the rubber itself is not an industrial problem; it's just not suitable for mass production).

The machining tool I used was a rotary tool with a cutting tool that didn't remove much material.

The finishing touch is done with a round file (it takes time, but I think it's possible to finish it using only a file).

Diamond file set
These diamond files offer great value for money. The round files, in particular, are very useful. The 5-piece set is highly recommended.

The idea is to trim it to match the original, beautiful shape of the frame, as shown in the photo below.

hereAn important point to note is that if you widen the hole too much, the initial velocity may exceed the legal limit, so you must make sure it stays within the legal regulations.

All that's left is to remove any remaining shavings and carefully assemble the magazine, making sure the gas route packing doesn't get damaged.

I had a total of three magazines, so repeating this process three times was a bit of a pain.

The customization is now complete.

Live-fire performance verification

We will check the shooting performance after customization.

The conditions were a CO2 cylinder (Baton product), magazine surface temperature of 26.6°C, room temperature of 23°C, and 25 rounds loaded (G&G bio BBs 0.2g).

We'll measure the initial velocity at the amount of hop-up that will likely result in the peak velocity (since I've modified the hop-up arm, I'll only apply a very small amount of hop-up).

Second shot

In the case of CO1-powered models, the first shot often comes out at a higher velocity, so this is the initial velocity after firing a few shots (around the 21st shot).

The beginning of the second magazine

It's now consistently working well, with a speed of 83-84 m/s at 0.2g.

The initial velocity was roughly the same as what I saw in the pre-release prototype reviews from various shops. In my personal opinion, this product was originally designed to have an initial velocity of 83-84 m/s with 0.2g BBs, but I think the performance has decreased because the gas route packing in the mass-produced magazines is poorly molded (the mass-produced version has an initial velocity of around 75 m/s with 0.2g BBs, plus there is a lot of variation in initial velocity).

Introduction article on chronographs

Fuel efficiency

Next is fuel efficiency.

This is the weight of the magazine before firing.

This is the weight of a magazine after firing 25 rounds.

3.5g of gas was used for 25 shots, which works out to 0.14g per shot. Out of the box, gas consumption was 0.11g per shot, which is slightly worse (but I still think it's good fuel efficiency).

According to the research, the CO2 cylinder holds 12±1g, so it should be able to fire about 85 rounds (3 magazines + a little extra).

When I actually tested it to its limits, the first three magazines worked with almost no performance degradation, and it started to get difficult from the middle of the fourth magazine (roughly as expected).

After that, I measured each shot using one CO2 cylinder and managed to maintain an initial velocity of around 80 m/s with 0.2g BBs up to the 80th shot, and was able to fire up to the 93rd shot. Since I was able to fire over 90 shots in a fairly rapid-fire state, if you fire with breaks in between, you might be able to fire around 100-110 shots like in other review articles.

Finally, here's a video of it in operation.

Before customization (room temperature 24℃, after firing 25 rounds from one magazine).

Baton Glock 17 CO2 GBB, straight out of the box, fully functional.

After customization (room temperature 24℃, after firing 25 rounds from one magazine).

Baton BG-17 CO2 GBB (operational after customization)

Since it already has a good crispness, there isn't much difference, but if you look closely, it seems like the blowback sound has changed.

Ballistics confirmation

I went airsofting and checked the trajectory of the bullets.

The location is Yanex.

It's like a microwave.

The conditions were such that the temperature was around 0°C.

This is a ballistic trajectory image.

With 0.25g BBs, the muzzle velocity was 78m/s, which is as high as a regular electric airsoft gun, resulting in a surprisingly good trajectory for a handgun.

Even with the iron sights on a handgun, I could hit a frying pan about 30cm in diameter with ease at a distance of 20m. However, because it was a handgun, at 40m, I could only aim for the upper body of a man-sized target.

It seems to have quite good accuracy and range.

Because the hop-up protrusion has been increased, with 0.2g BBs, even at the minimum hop setting, the hop tends to be slightly too strong. Incidentally, with 0.25g BBs, turning the hop-up dial about 1/3 to 1/2 of the way was about right.

It seems like it could handle slightly heavier ammunition as well.

Given this level of accuracy and range, it would be even more interesting to convert it into a carbine and mount optical sights for precision shooting.

That concludes the verification.

G&G Bio-Bullets 0.2g
It's inexpensive and accurate, so I use it for a wide range of purposes, from performance testing to airsoft games. It's been my favorite since it first came to Japan (around 2008). It lasts a long time for a biodegradable product.

G&G Bio-Bullets 0.25g
It's 0.25g. I generally use 0.25g BBs when playing airsoft.

Summary

It took quite a bit of effort, but I was able to achieve all the goals I had set for the customization.

The potential is generally high, but the mass production precision of some parts doesn't quite match the design, so we had to compensate with custom work.

I suspect that, like with Mr. Button's previous models, this issue will be addressed as the production batch progresses.

One thing that particularly caught my attention was that during the review, it was unclear whether the clearly inferior shooting performance compared to the previous model was intentional or accidental, but after customizing it, I think it wasn't intentional (even though they're both BG-17s, the prototype and the mass-produced version are too different).

It simply seems that the mass production molding precision of the gas route packing is poor (the BM-45 packing is molded beautifully).

If you put in a little effort to finish it nicely yourself, it seems you can achieve performance comparable to other models from Baton (the fuel efficiency didn't worsen much, and the muzzle velocity was decent; in the end, the only thing I replaced was the barrel).

I expect that compatible parts will be sold with each subsequent production run, so I will keep an eye on that.

Thank you for bearing with me through this lengthy explanation.

I replaced the hammer with a damage prevention hammer, which was distributed in late May 2023.

This time, I've written an article explaining the operating mechanism of the slide that I customized, so if you're interested, please take a look.

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.