This time, I'll be reviewing the Maruzen CA870 Charger, which a friend commissioned me to customize.
The contents are in their original, out-of-the-box state, with only the rail and front sight attached to the exterior.
However, this is the first time I've featured an airsoft gun on this blog, and it's a commissioned piece. I have several others in my collection, including a Tanaka M40A1, a Gew 33/40, and a Snow Wolf SV-98, but I haven't had the chance to feature them yet. I'll introduce them soon.
Since many experienced users have already provided detailed reviews of the CA870, I'll keep this brief.
Later, disassemble itIt turns out this product is the old Hop version. The old Hop version was likely discontinued in 2014, so most people probably already own the New Hop version.
For those considering purchasing TheUnless it's a very old used item, only the NEW HOP version is sold, not the old HOP version.
Therefore, I'm reviewing the NEW HOP version, so if you want to know about the NEW HOP version, please click the link.
Now let's take a look at the appearance of the Maruzen CA870 Charger (old hop-up version).
*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.
appearance
Let's start with a side view, as usual.
Other side
This model probably doesn't exist in the real world, but it has a nice feel to it.
Since it's a charger, it has a pistol grip and an M4-style adjustable stock, making it seem easy to use.
Next, the stock is fully extended.
Other side
This will be quite long.
The stock position can be adjusted in a total of 5 stages.
I don't think most people will ever use it at its maximum length. For me, at 175cm tall, the third position from the shortest setting feels just right.
The velocity check stickers suggest that these were widely used at F2 Plant in Sano City, Tochigi Prefecture.
Around the trigger
Next, let's look at the trigger mechanism.
Other side
The safety is a cross-bolt type, commonly found on real shotguns. It's simply a matter of pressing a button.
Next, let's take a look at the important fore-end of this product.
This is the range of motion of the pump action.
Forehand end pulled back
The movable range is about 10cm, and the cocking action feels relatively light.
I think even women can easily cock the gun by pulling back the fore-end and simultaneously pushing forward with the hand holding the grip.
Grip
Next is the grip.
Unlike electric airsoft guns, there is no motor inside the grip, so it can be made thinner.
I haven't looked into it properly, so I'm not entirely confident, but it looks like a grip for a gas blowback M4 might fit. Depending on the specific grip, some modification might be necessary.
Bullet feeding port
Next, let's look at the ammunition feeding port.
It's a fairly simple mechanism. The internal frame appears to be made of zinc.
Hop adjustment section
Next is the hop adjustment section.
This type is adjusted using a hexagonal grub screw near the base of the outer barrel.
Personally, I'd like it to be adjustable without tools and to have a visual indicator of the hop-up strength.
I won't do it since I wasn't asked to, but you could cut a hex wrench to a convenient length and glue it to a grub screw to create a tool-free adjustment mechanism.
Site
Finally, let's look at the website-related aspects.
The original, out-of-the-box version doesn't come with sights or a top rail, so the owner, a friend of mine, apparently added a rail and a front fiber optic sight.
Site Picture
Front sight
The front sight is the type that fits into the outer barrel and isn't fixed in place, so it's not very accurate, but it looks cool.
The owner's custom-designed two-tiered rail system allows you to peek at the front sight through the gaps in the rails. My friend and I prioritize safety and use Tokyo Marui's Pro Goggles, which means our eye level is higher when cheek welded, so a riser mount is essential for us.
Furthermore, aftermarket rail systems require drilling holes in the main receiver, which seems like it would be a hassle to install.
・G&P CA870 receiver rail
It's fairly expensive. If you want to do it cheaply, you can buy a suitable general-purpose rail, drill holes in the receiver, and attach it; that should cost around 1500 yen.
• High-quality front sight for CA870
It's a matter of preference. I think many people use optical equipment, so you should install it based on your preferred appearance.
Tokyo Marui High Mount Rail
It's useful to have one for height adjustment, not just for the CA870.
If you just want to attach a top rail cheaply and easily, you can prepare a rail like the one shown below and drill holes in the top surface of the receiver; this should allow you to attach it relatively easily and inexpensively.
- No-brand general-purpose rail
Magazine
Finally, let's take a look at the magazine.
This is an excellent and inexpensive magazine, costing less than 750 yen (including tax) at its original price.
The magazine release button isn't on the main body, but rather a non-slip button in the center of the magazine, which allows it to be removed.
This is a convenient feature that's only possible because it's a fictional gun.
Magazine lip section
The magazine lip is made of resin and has a nice, moderate bullet-holding capacity.
With a strong feeding spring and a metal lip, the BBs can sometimes get worn down, so this product is a good combination.
Now that I've given you a general overview of the exterior, let me explain a little about Maruzen's specialty, fiberglass resin.
A little story about fiberglass
Simply put, fiberglass is a resin product made stronger by mixing glass with a resin material.
It's generally called FRP (Fiber Reinforced Plastic), and if it's made of glass fibers, it's called GFRP, and if it's made of carbon fibers, it's called CFRP.
CFRP is a familiar material to car enthusiasts; a well-known example is the bodywork of Formula 1 cars, which are made from this material.
Based on my experience, this product appears to be a mixture of nylon resin and glass fibers. It's likely labeled PA66-G50, meaning it's a material made by mixing 66 nylon with about 50% glass fibers.
This material combines the hardness provided by glass with the toughness of nylon, resulting in a strong, heat-resistant material.
However, it has high water and oil absorption properties, which can cause dimensional changes. But if this is taken into account during the design phase, it won't be a problem, and as long as the design is correct, it's a very usable material.
During my time as an engine designer, I also promoted the use of FRP for weight reduction, but the main concern is swelling due to water and oil absorption. I would conduct experiments to investigate how much the parts would swell before actually designing them, taking dimensional changes into account.
As a side note, the reason why the surface of Maruzen's resin products feels different from others is because of the rough texture created by the use of glass fibers.
In other words, it's a material that doesn't look very good, so it's not often used for decorative parts in the automotive industry.
It breaks in an interesting way; instead of cracking like other resins, it tears apart.
Next, we will check the actual firing performance.
Live-fire performance verification
Now, as usual, let's take a look at the actual shooting performance.
The conditions were a temperature of around 23°C (I'm noting the temperature because it affects the hop-up), and I shot with S&T's Bio 0.2g BBs. The hop-up was set to the weakest setting.
88.33 m/s is decent, but after several shots, the reading varies from 86 m/s to 88 m/s.
Next, here's a look at the live-action footage.
As you can see, the spring noise is terrible.
Overall, the product is well-made, with a muzzle velocity of 88 m/s at 0.2g.
If you're interested, please also check out my review of the chronograph.
Incidentally, the trigger pull is quite light. Like a two-stage trigger, there's a few millimeters of play before it gets heavier and you can feel the sear disengage.
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.
Overhaul and customization direction
The owner's requests for future customizations include slightly increasing the muzzle velocity and reducing noise, so we will address those in the next section.
- Elimination of spring noise
- Make it possible to attach a silencer.
Thorough polishing of moving parts
• Application of high-quality grease
- Hop packing change
- Initial velocity adjustment: Approximately 95 m/s or less with 0.2g BBs.
- Cleaning the exterior
We will search for parts and customize the bike in this direction.
Stay tuned for the next episode: Disassembly & Customization!
Finally, as is customary, here's a product introduction: the old HOP version is basically no longer in stock on the market, so if you're considering purchasing the Maruzen CA870 series, please refer to the review article for the new HOP version.
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