In the previous post, I reviewed the WE Dragunov SVD GBB and checked its initial performance.

This time, we'll be making adjustments and customizations.

As usual, we'll set the goals for adjustments and customizations and select the parts.

Setting goals for adjustments and customizations.

To summarize the points that I noticed during the previous live-fire performance test:

2 points.

There aren't that many items, but it looks like it will be quite a task.

The parts I chose are the following:

We will incorporate these.

The goal is to stabilize the muzzle velocity while making the most of the excessively long inner barrel by using a barrel with an inner diameter of 6.06mm up to 250mm and an inner diameter of 7.5mm beyond that, resulting in an effective barrel length of 250mm.

To improve performance, the recoil spring will be replaced with a softer, longer spring.

The instability in initial velocity can be addressed by slightly strengthening the barrel and flow valve springs to increase the amount of gas supplied to the firing side.

The next step is to polish and grease any areas that need attention.

We'll proceed with the customization while disassembling it.

Disassembly of the exterior

I started by removing the handguard. I later realized that disassembling the hand cover wasn't necessary for this particular project.

Turn the lever located at the tip of the handguard.

Bend the lever inward and rotate it. It's quite stiff.

Next, slide the metal fitting (sheet metal) that holds the handguard in place towards the muzzle.

This makes it easy to remove the handguard.

Removing the handguard reveals the gas piston. It actually works properly, which is quite realistic. As expected from a gas blowback gun.

Next, we'll remove the top cover of the receiver. Turn the lever located behind the selector switch.

Rotate the lever until the hole fits into the projection at the base of the grip stock.

This will allow you to remove the top cover.

Now the exterior can be disassembled. It's impressive how no tools are needed up to this point, a testament to the quality of gas blowback airsoft guns.

Bolt disassembly

Now that the top cover is off, remove the bolts.

Before removing the bolt, remove the bolt stopper, which is made of resin.

It's simply stuck in there, so I'll pull it out.

This is the shape of the part.

The plastic perforations included as accessories were actually bolt stoppers.

Next, remove the bolt. You can remove it by moving the bolt to the rear end of the receiver and lifting it up.

Since I had the opportunity, I decided to measure the weight of the bolt.

It weighed nearly 300g. The recoil is powerful and impressive, but with HFC-134a pressure, it's a bit heavy and might affect its operation. For reference, the KSC AK-74 has a bolt that weighs 206g, so the SVD has a considerably heavy bolt.

Next, we'll disassemble the bolt. There's a pin near the rear end of the bolt, so we'll remove it with a punch.

Next, remove the slotted bolts located on both sides of the sliding groove in the center of the bolt.

This allows you to remove the blowback engine.

You can disassemble this blowback engine by removing the pin located near the center.

The parts, from top to bottom in the photo, are the cylinder, flow valve spring, flow valve, nozzle, and return spring.

This allows you to completely disassemble the bolt.

For disassembling the pin-type mechanisms commonly found in gas blowback guns, we recommend the following three tools.

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.

If you're interested, I've made a video explaining the operating mechanism of gas blowback guns, so please take a look. If you consider the bolt as the slide, the principle is the same.

Disassembly of the inner barrel and hop-up chamber

Remove the grub screw that secures the receiver to the hop-up chamber.

As it is, there isn't enough space to work properly, so if you flip the tangent sight upside down, you can easily access the grub screw.

After removing the grub screw, move the inner barrel, along with the chamber, to the rear.

We'll disassemble the hop-up chamber in this state. Disassembling the outer barrel is necessary to remove the inner barrel and hop-up chamber separately, which is troublesome, so we'll disassemble them here.

Rotate the hop-up chamber sideways and remove the screws that disassemble the chamber.

Now you can disassemble the hop chamber. The components are shown in the following picture.

Let's remove the hop packing as well. The hop's bucking rubber is cylindrical, but for some reason the packing is a long, flat type. It seems pointless to use a long packing if the bucking rubber is cylindrical.

Next, before removing the remaining inner barrel, remove the flash hider. It's only held in place by a reverse thread.

Once the flash hider is removed, the inner barrel can be detached from the outer barrel towards the muzzle.

I thought it would have a long inner barrel, but for some reason it was a 350mm long barrel with an inner diameter of 6.06mm. However, 350mm is still long enough, so I'll replace it later.

This completes the disassembly of the barrel area.

Disassembly of the trigger area

Turn the selector counterclockwise.

By rotating it to a certain angle, align the selector retaining rod on the selector shaft with the groove in the receiver hole, and then remove the selector to the right as shown in the picture.

By the way, the removed selectors look like this:

Next, remove the trigger assembly. Hold the trigger guard and apply downward pressure while turning it counterclockwise to remove it. Note that the hammer will not come off unless it is laid flat.

Now you can remove the trigger assembly.

I've never seen the real thing, but this looks quite realistic. The hammer spring is a little too strong and it seems like the hammer might break, but since the hammer is made of iron, it'll probably be fine.

If you want to weaken the hammer spring, you can do so by removing the spring and bending it slightly.

Next, remove the valve knocker assembly. Remove the screws shown in the picture. They are extremely tight due to threadlocker.

This is where it gets a little tricky. First, flip the receiver over and lift the protrusion (bolt stop lever) on the right side of the receiver while firmly pushing the knocker in the direction you were using it.

This will allow you to remove the parts around the knocker.

To briefly explain the parts around the knocker, the valve knocker that strikes the magazine valve is shown in the following picture.

Next, there's a part that retracts the valve knocker to stop the gas release when the bolt has finished blowing back and moving, and that's what's shown in the next picture.

Finally, it has a bolt stop lever for when the magazine runs out of ammunition.

I think we've now disassembled the basic components.

All that's left are the stock, outer barrel assembly, and recoil spring.

I'll do the recoil spring disassembly, overall adjustment, and customization next time.

WE-tech SVD Dragunov Aluminum Frame, Polymer Stock, Handguard
This is the Dragunov featured in this article.

WE-tech SVD Dragunov Aluminum Frame, Faux Wood Stock, Handguard
This is a fake wood version of the Dragunov featured in this article.

WE-tech SVD Dragunov Magazine
This is a spare magazine.