In the previous post, I showed how to disassemble and customize the slide of the UMAREX/VFC VP9.

This time, we'll mainly be showing you how to disassemble and customize the trigger mechanism on the frame side.

Just to recap, let's review the custom objectives.

Customization goals and procured parts

First, let's look at the custom goals.

We will proceed with disassembly and customization to achieve the remaining customization goals.

This time, there are no parts to be procured for the frame; the work mainly involves machining and polishing.

Now, let's proceed with the disassembly and customization.

Grip panel replacement

First, we'll replace the included grip panels.

Remove the pins that secure the grip panels on the frame. They are located at the bottom of the backstrap.

We'll remove the pins using a pin punch and a maintenance stand.

Once the pin is removed, the replaceable part can be taken off. Incidentally, not just with this product, but with airsoft guns in general, a lot of fasteners are secured with pins, so it's a good idea to have a pin punch and a maintenance stand.

It's not impossible to do it with a hex wrench, but it will definitely bend, and it's generally difficult to do.

I'd like to recommend a pin punch and a maintenance stand.

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.

The removed part will look like the following picture.

side.

Back side.

This time, we'll be installing the S size. Let's check the parts.

The back of each piece has markings indicating the placement and size of the parts, making it easy to identify even if it gets mixed up with other sizes.

Once you attach this, the grip will look like this.

It's hard to tell from the photos, but it's considerably narrower than the standard M size. It's quite surprising. I think most Japanese people would probably fit the S size. I wonder what the Self-Defense Forces will do as they adopt these newer sizes?

This completes the replacement of the grip panels.

Next, we'll replace the takedown lever that comes with the special combo.

Replacement of the takedown lever

To remove the takedown lever, rotate the lever as shown in the following picture.

Next, lightly tap the shaft of the takedown lever from the opposite side and it will come out.

Let's compare the genuine product with the included accessories here.

The parts included in the Special Combo are likely made of iron and have a higher quality feel.

Now we'll install it, which is very simple. Just reverse the disassembly process and insert the lever at the position shown in the following photo.

Now, simply turn the lever back to its original position and you're done.

Incidentally, this product has a hidden feature that isn't mentioned anywhere: a hexagonal screw that allows you to adjust the trigger pull distance.

This allows you to adjust it, but be careful when adjusting it, as reducing the trigger pull may prevent the trigger from reaching the point where the sear drops.

I'll leave it in its original position.

Next, I'll show you how to disassemble and customize the hammer mechanism, which is the main focus of this tutorial.

Removal of the hammer mechanism

First, remove the pin to take out the hammer unit.

The pin is positioned where your thumb rests when you grip the club. Be careful, as the pin is extremely tightly embedded.

Once the pin is removed, the hammer unit is fitted into the frame, so slide it out as shown in the next picture. The trick is to hold down the trigger to give the trigger bar some slack, which makes it easier to remove.

Now you can lift it up and take out the hammer unit.

Let's take a look at the hammer unit that we removed.

First, here's a side view.

This shear acts to hold the hammer in place if it falls over.

Furthermore, it's connected to the trigger bar, and when you pull the trigger, the sear moves, releasing the hammer it was holding down. Be careful, because if you don't hold it down with your finger, the sear and spring will fly off somewhere.

Next, let's look at it from the top.

Be careful, as the knocker return mechanism is also prone to flying off due to its spring.

Next is the back.

This photograph clearly illustrates the mechanism.

It's unusual to see a coil spring used to return the knocker; most products use a torsion spring.

Next is the knocker return side.

When this knocker return is pressed by the slide, the knocker retracts and the gas discharge stops.

Next, let's look at the knocker side.

This knocker is pushed by the hammer, striking the valve in the magazine, and the gas flows into the slide.

In a mechanism unique to gas guns, even if the hammer is knocked down again by the slide, the knocker does not retract and gas continues to flow. The gas continues to press against the magazine valve until the knocker return mechanism, which was mentioned earlier, is pressed by the slide, thus ensuring that gas continues to flow even after the bullet has been fired until the blowback is complete.

This article explains the mechanism of gas blowback guns, including the trigger, hammer, and magazine. Please read on if you're interested.

Next, we'll disassemble and customize the hammer unit.

Hammer unit disassembly and customization

Disassembly itself is quite easy. Carefully remove each part, making sure not to let it fly off due to the springs.

First, remove the knocker return.

Next, remove the shear on the opposite side. Once the shear is removed, you will see the pin, so remove the pin as well.

The pins can be removed with just a little force, so be careful not to let them fly away.

Next, we'll remove the knocker's return spring.

Now you can take it apart.

I'll leave the complete set of hammer unit parts here.

Here, we'll slightly weaken the hammer spring, which is too strong for the custom target.

First, here's the original condition.

I want to replace this, but I don't have a custom part, so I'll have to modify it somehow.

Apparently, a third-party company sells a spring called "Winter Hammer Spring" with a load reduced by about 20-30%, but it was out of stock everywhere (it seems to have the same number of turns but the coil diameter is thinner).

Since the spring constant cannot be changed during processing, the initial load is reduced by bending and moving the point where the spring catches.

Be careful not to bend it too much, as this will reduce the load and prevent the knocker from pressing the magazine valve. As a guideline for adjustment, it should be fine if the trigger weight feels the same as that of domestic products after assembly.

You can use the amount of bending shown in the photo as a reference, but we recommend adjusting it little by little by repeatedly bending and assembling.

This method is an effective customization for improving the operation of gas blowback pistols, whether handguns or rifles, that are designed for high pressure, when using alternative refrigerants (HFC-134a) (many overseas-made pistols are designed for high-pressure gas and have heavy hammer springs).

Next, we will proceed with the adjustments to achieve the custom goal of improving the trigger feel.

The stock trigger has a slightly rough, gritty feel. This is because the part of the rear chassis that the trigger bar contacts is painted, and the rough surface causes a gritty feeling.

Therefore, I will polish the contact surface with the trigger bar. While I'm at it, I'll also polish the contact surface with the sear.

I also polish the part on the opposite side where the knocker return makes contact.

You could polish it with sandpaper, but I find that too much trouble, so I use a rotary tool to buff it.

However, be careful not to overdo the polishing, as excessive changes in dimensions can cause malfunctions.

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.

After polishing

I think it's best if it feels smooth to the touch and the scalp is barely visible.

Next, apply Bellhammer Gold Grease No. 2 to each part and carefully assemble them.

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.

Now we'll assemble the adjusted parts.

A tip for assembly is to first assemble the hammer and knocker and insert a pin punch in place of the pin. This is because the hammer spring is stiff, making it difficult to insert the pin directly.

Insert the pins while adjusting the position of the holes in each part with a pin punch.

All that's left is to assemble the remaining parts, and then you're done.

For reference in case you get stuck, I've included a picture of the completed hammer unit.

Hammer unit left side

Hammer unit bottom

The sear spring on the right side of the hammer unit is not assembled because it tends to fly off.

Hammer unit knocker section

Once you've done this much, just assemble the hammer unit into the frame and you're done.

When assembling, holding down the trigger while attaching the trigger bar to the sear increases the bar's freedom of movement, making assembly easier.

All that's left is to check that all the parts are working correctly, and then you're done. As a final touch, apply some Bellhammer Gold Grease No. 2 to the front of the frame, where it slides against the slide, and you're finished.

This completes the frame disassembly and customization.

This post has gotten a bit long, so I'll cover replacing the magazine's gas injection valve and testing its shooting performance in the next installment.

Please come along if you like.

The custom parts used this time are just whatever I had on hand. DIY fabrication makes it priceless.

Next is the main unit.

・UMAREX/VFC VP9 special comb DX/JP version
It comes with a steel extractor, a luminous sight set, and a slide takedown lever.

・UMAREX/VFC VP9 STD JP version
The extractor, sight, and lever are made of aluminum. The difference is purely cosmetic.

・Le Pair Magazine
It seems they've restocked, and the price is now reasonable. I recommend getting it while it's still in stock.

・Injection valve for domestic gases
I recommend it (but be sure to use genuine O-rings).