Maruzen CA870 Charger NEW HOP Disassembly

In my previous article, I wrote a review of the Maruzen CA870 Charger NEW HOP straight out of the box.

This time, we'll be disassembling a CA870 straight out of the box to examine its assembly quality and component quality.

We'll start by disassembling the exterior.

Disassembly of the exterior

I'll start removing the stock.

Extend the trekking pole all the way to the end, then lift and pull the part shown in the picture to detach it.

Next, although it's not necessary to disassemble the main body, let's try removing the grip.

If you look at the grip from below, you'll see a screw, so remove it.

It's a bit stiff, so you can remove it by pulling the grip with some force.

The structure at the base of the grip looks similar to that of a gas blowback gun, but the shape is subtly different (and completely different from an electric gun). You may need to modify the grip if you plan to replace it.

Next, remove the rear block (stock tube).

There's a screw at the base of the stock tube, so remove it.

It's a fairly long screw, so do your best to remove it.

Once the screws are removed, the rear block (stock tube) will come off.

Next, shift your gaze forward.

Remove the cap from the end of the foregrip tube.

When the cap is removed, the outer barrel also comes off.

Now let's take a look at the base of the inner barrel.

There was some looseness in the inner barrel's mounting. However, this looseness doesn't significantly affect performance, and it's necessary as a buffer during assembly, since the outer barrel determines the position of the inner barrel.

I suspect that they intentionally leave a bit of play to avoid assembly and cost issues if they were to use a more rigid positioning mechanism at the base.

Next, we'll remove the foregrip tube. This is easy; simply twist the tube counterclockwise.

Rotate the tube as shown in the picture.

This will remove the tube.

Next, we will disassemble the exterior of the main unit.

First, there's a pin in the position shown in the picture, so remove it with a pin punch. Unusually for this type of structure, there's no specific direction.

You can remove it with a thick hex wrench or something similar even without a pin punch, but it's better to use a punch if possible.

I've disassembled several air pumps so far, and I've used a pin punch, maintenance block, and plastic hammer almost 100% of the time, so if you're going to customize it, I think it's worth having them on hand.

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.

Vessel Plastic Hammer
It's inexpensive, sturdy, and long-lasting. For a good balance of control and power, the 1-pound size is recommended.

Next, remove the hexagonal bolts on the left and right sides of the main unit.

On the other side.

Removing the screws will allow you to remove the entire trigger guard assembly.

Looking at the trigger guard reveals the safety mechanism.

Take a closer look at the grooves in the photo.

Safety off.

When the safety is turned on, the groove moves to the right side of the photo, causing the groove to shift.

It seems that this groove, when misaligned, obstructs the trigger's movement, preventing it from firing. I think it's a simple and reliable mechanism.

Next, remove the cover from the main unit. This will simply slide off forward.

There are three points to note here.

The first point is the ejection port. It's simply there for decoration, so be careful not to forget about it.

Secondly, the part shown in the following picture is prone to falling off, so please be careful not to lose it.

I recommend removing it immediately and keeping it safe so you don't lose it.

The third point is the resin part located at the front.

You need to remove this part, otherwise you won't be able to disassemble the main unit, so be sure to remove it.

This completes the disassembly of the exterior.

Disassembly of the main unit and gearbox

Now we'll start disassembling the mechanical parts.

Remove the pin (spring pin) that positions the gearbox (the photo shows the screw being removed first, but I think it's better to remove the pin first).

This part is quite stiff and difficult to remove, but you can disassemble it by pushing the pin in about halfway, so there's no need to force it out.

Next, remove the screws holding the gearbox in place. Unfortunately, these screws are Torx T8s.

Torx screws are common in Japanese manufacturers' products, likely for their anti-disassembly features. Since I don't often work on Japanese-made products, I use the following very inexpensive Torx tool. Because of its low price, it can't apply much torque, but it's sufficient for airsoft applications.

Torx screwdriver set
This set will generally suffice for most needs. It's inexpensive. For those who plan to use it seriously, I recommend branded products.

Next, carefully open the main body, paying attention to the bar that will be used to cock the gun.

Since we're here, let's take a look at the structure.

This is the trigger mechanism and spring section; it's a fairly simple mechanism.

This spring has a very small outer diameter, a small winding pitch, and a large number of windings.

The trigger mechanism will be explained in the adjustment and customization section.

Next is the piston and cylinder section.

The piston is pushed by a cocking bar.

Next are the nozzle, tappet, and hop-up section.

The nozzle is integrated with the cylinder, ensuring perfect airtightness.

The hop-up mechanism has also been redesigned and is similar to that of typical electric airsoft guns. I believe the shape changes accompanying the hop-up modification were achieved by modifying existing molds.

Next, we will remove each component. None of the components are secured with screws or pins, so they can be easily removed.

There's just one thing to note: there's a spring behind the rod-like part shown in the next picture.

This completes the basic disassembly.

Overall, the assembly was neat and well done, but only a minimal amount of grease and lubricant was applied.

Next, let's look at some of the parts.

Checking the main components

First, let's look at the cylinder. The nozzle and tappet are integrated into one unit.

The cylinder, nozzle, and tappet all appear to be thick-walled and sturdy. Therefore, although I wouldn't recommend it, I think it wouldn't break even if you cocked it roughly.

Next is the piston. It has a rather unusual shape.

When viewed from the back, the shape of the area where the spring fits is diamond-shaped.

Given its shape, it seems like it would be troublesome to increase the spring's strength on the piston side to boost the initial velocity.

Next, let's look at hop-related topics.

This is the inner barrel assembly.

It appears that the positioning is done using the pins that came with the main unit.

Let's break this down.

Let's take a look at the hop-up window on the inner barrel.

The craftsmanship is meticulous, like that of a custom part. You can feel the dedication to distance and accuracy.

This is the tip of the barrel. It doesn't seem to have the trendy tapered design.

Since it's made of brass, additional processing such as tapering is easy, so you can shape it to your liking.

Next, let's look at the hop packing.

It has a long bump, resulting in a long-range hop-up. The rubber is likely nitrile rubber and is quite soft. Considering handling and temperature differences depending on the season, it seems like a good choice. However, because it's soft rubber, it might wear out a little faster if used with heavy BBs and strong hop-up.

Next is the hop arm.

This hop-up arm is similar to those found in typical electric airsoft guns. This should significantly improve the trajectory compared to the old hop-up system.

This is the part that presses against the packing of the hop-up arm.

The arm is also shaped to accommodate long-range hop-up. NEW HOP was released around 2014, and at that time, it is believed that this long-range hop-up achieved exceptional range and accuracy.

I think it's fantastic, with a composition that's on par with the latest hops.

Finally, let's take a look at the main body casing and gearbox.

I previously disassembled the old HOP version, and it seems that when they switched to NEW HOP, they also performed maintenance at the same time as modifying the mold. The parts themselves don't seem to have many burrs or scratches.

However, since the mold has been in use since 2014, there are signs of wear and tear to some extent.

This concludes the parts check.

Summary and custom goals

As expected of a domestically produced product, I didn't see any issues. I was impressed by the high level of craftsmanship that comes from years of manufacturing competition-grade airsoft guns.

The newly redesigned hop-up mechanism is particularly impressive. It's a significant improvement over the old system that used a grub screw to apply strong pressure at a single point, now utilizing an arm to allow for longer-lasting hop-up.

The structure employs a very simple and reliable mechanism. Although it falls under the air-cocking category, its structure is much more similar to an electric airsoft gun than a bolt-action one.

It was like a manual electric airsoft gun where you pull the piston by hand instead of using a motor and gears to pull it.

Because of its simple structure, disassembly and reassembly are quite easy, and you don't need any special tools other than Torx screws, so I think it's perfect for those with little experience in disassembling things (although there aren't many parts to tinker with).

Next, let's consider areas for improvement.

It's quite excellent, so there aren't many issues, but the following points bothered me.

I'll keep these points in mind as I make adjustments and customizations next time. Please join me if you're interested.

Maruzen CA870 Charger NEW HOP
This is the product I introduced this time. The old Hop version is almost impossible to find on the market, but the NEW HOP version has a sticker on the box, so please be careful when purchasing.

From here on, the basic structure is the same, only the exterior is different, so the same customizations should be possible.

Maruzen CA870 Stock
I personally prefer the curved rifle style, the traditional style.

Maruzen CA870 Sawed-off
This is the lightest and most compact type. I think it's suitable for those who like to charge in aggressively. Personally, I find it easier to cock with a stock.

Maruzen CA870 Bulldog
This model is lightweight, compact, and features a grip on the fore-end for improved rapid-fire capabilities. It might be the most suitable model for airsoft games.

G&P M870 shotgun shell loading port style magazine, 22 rounds capacity.
Personally, I think it looks cool to put this magazine on a CA870 stock to give it an M870-like appearance. The magazine capacity is reduced, but it still has 22 rounds, so I don't think it's a problem.