KSC Mk23 SOCOM Pistol CO2 ABS Custom Completed: Slide Main

Last time, we continued customizing the frame of an early production run KSC Mk23 SOCOM pistol CO2 ABS.

In this customization, we will address the remaining challenges.

Based on these considerations, this time we will focus on customizing the slide mechanism and proceed until completion.

Customization and assembly of blowback units

First, we'll customize the bleach.

Upper

lower side

As usual, I'll polish the sliding parts of the breech with a rotary tool 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.

The bleach processed with a rotary tool will look like this.

After upper side processing

After lower side processing

Next, we will customize the piston unit (HK piston unit).

We will be modifying the holes in the piston unit, which is one of the customization options.

I made a fatal mistake while handling this piston unit (HK piston unit). I was spraying KSC gun oil into the piston unit to remove metal shavings (waste generated during machining) from drilling holes. As a result, oil got inside the piston unit, causing the nozzle to move sluggishly and preventing the gun from firing.

As a solution, I asked KSC's service department to repair it, and they replaced the piston unit with a new one, along with a message saying that lubrication of the piston unit is not allowed (as stated in the instruction manual) (this explains the long gap between my previous posts).

Video of a normal nozzle in operation

KSC Mk23 SOCOM Pistol CO2 Nozzle Function: Normal

Abnormal nozzle movement (slow nozzle return)

FullSizeRenderKSC Mk23 SOCOM Pistol CO2 Nozzle Operation Malfunction

If the nozzle becomes stiff in the future, I'll try wiping it with parts cleaner instead of applying oil (silicone spray) (I'm worried about damaging the O-ring).

Due to these circumstances, I abandoned the idea of ​​customizing the piston unit and proceeded to assemble the blowback unit. (I was inexperienced).

Next, I apply my usual Bellhammer Gold Grease to the bleach.

Start painting from the top side.

The upper surface is a part that slides against the resin cylinder, so apply Bellhammer Gold Grease No. 0 to it.

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, paint the underside (you can paint it later if you prefer).

The underside slides against the hammer mechanism unit, which is a metal part of the frame, so apply Bell Hammer Gold Grease No. 2 to it.

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.

Next, we will assemble the piston unit and the breech.

Next, attach the nozzle return spring to the cylinder.

This is the back side.

Next, we'll install the firing pin at the rear end of the breech.

Insert the firing pin shown in the photo above into the hole at the rear of the breech and secure it with the pin.

Assemble the completed blowback unit into the slide.

Next, we'll assemble the extractor.

Finally, tighten the screw into the hole in the center of the rear sight, and you're done. At this stage, you can move the rear sight left and right, so I adjusted it to the center.

Assembly of the inner barrel and hop-up chamber

Check the hop-up window on the inner barrel.

I was bothered by the edge of the hop-up window on the stock barrel, so I used the rotary tool I introduced in the article with a polishing bit to modify it.

This is a machined barrel.

Ideally, since I've disassembled it this far, I would have liked to replace the inner barrel with an aftermarket one, but because it uses a proprietary standard, I opted for a modified original barrel.

Next, we'll install the hop packing (make sure to insert the drum before installing the packing).

Normally, before assembling the hop-up packing, I would apply silicone grease to the hop-up window area of ​​the inner barrel to ensure airtightness, but since the packing seems to be made of silicone rubber, this time I only wrapped it with sealing tape.

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 rest is done by reassembling it in the same way as disassembling it.

Place the ball on the hop packing, assemble the clip, and then move the drum forward.

Be careful not to drop the ball when moving the drum forward.

Next, assemble the E-clip, then attach the barrel clip.

E-clips can be easily assembled with the following tools (it's difficult with needle-nose pliers).

Snap ring pliers (also suitable for shaft holes)
Since clips are sometimes used, it's handy to have one on hand.

Please note that the barrel clip has a specific assembly position.

Next, we'll assemble it into the outer barrel.

The outer barrel is fitted with fixing screws and movable parts to secure the inner barrel.

It is assembled.

The barrel assembly is now complete.

Assembling the slides

Apply grease to the recoil spring.

You could disassemble the recoil spring, but that's a hassle, so I compress the spring from the front and back and apply Bell Hammer No. 2 to the rod section (guide).

front side

The girl

Next, apply a thin layer of Bellhammer No. 0 to the outer barrel sliding surface of the slide.

All that's left is to assemble the barrel and recoil spring onto the slide, and the slide will be complete.

Before assembling the slide into the frame, apply grease to the frame side.

Apply Bellhammer No. 0 to the rail section that engages with the slide.

The top surface of the frame comes into contact with the slide's breech, so apply Bellhammer No. 2 to it.

Finally, assemble the slides and you're done.

Live-fire performance verification

We will check the shooting performance after customization.

The conditions were a CO2 cylinder (Baton product), a magazine surface temperature of 28.8°C, and a room temperature of 23°C, with 25 rounds loaded (VFC bio BBs 0.2g).

We'll apply a small amount of hop-up and measure the initial velocity.

Second shot

There was some variation, but it was roughly between 75 and 85.2 m/s. The only customization I made to the parts related to initial velocity was improving the airtightness of the hop-up packing, so it shouldn't be much different from out of the box.

Regarding the variability, there are some unavoidable aspects due to the structure, so I will explain a little.

Chronograph article

Causes of initial velocity variation

The mechanical blowback unit, a proprietary mechanism developed by KSC and not the more common negative pressure type, significantly contributes to this variation.

Let's focus on the gas route when a projectile is fired.

When viewed as a standalone nozzle unit

The photo above illustrates the situation where the bullet pushes the nozzle, causing gas to flow towards the firing side. Looking at the gas route, you can see that it's shaped to allow for smooth gas flow.

Next is a condition where the initial velocity is low due to variations (the nozzle is rotating).

When viewed as a standalone nozzle unit

As shown in the picture above, a column (wall) appears in the path of the gas flow, constricting the gas flow (pressure loss).

This difference affects the initial velocity, causing variations.

When actually firing the SOCOM, the nozzle rotates due to the gas flow and feeding mechanism, which changes the area of ​​the gas route through which the projectile is fired, resulting in a slightly larger variation in muzzle velocity.

If it were possible to disassemble it, I would have liked to devise a way to prevent the nozzle from rotating, but I couldn't disassemble it, so I gave up.

Incidentally, while vacuum-type air intakes previously had some variation in initial velocity due to the rotation of the flow valve, recent models have a structure where the flow valve does not rotate, significantly reducing the variation.

As expected of the vacuum type, which is the mainstream method, it seems that a great deal of ingenuity has been accumulated to make it work.

Explanation of the mechanism of a negative-pressure gas blowback system

Fuel efficiency check and operation video

This is the weight of the magazine with a new carbon dioxide cylinder installed.

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

The gas consumption for 25 shots is 4.0g, which works out to 0.16g per shot. Incidentally, the gas consumption was the same even straight out of the box, at 0.16g per shot.

Since I had the opportunity, I tested how many rounds it could fire, and it managed to fire up to 85 rounds (the slide stop didn't engage).

Out of the box, it could only fire about 70 rounds, but I was able to extend it by about 15 rounds to 85 (it managed to maintain around 70 m/s until about the 75th round). However, as the instruction manual states, it's best to assume that it will only function reliably with two magazines.

Next is a video of it in operation. The condition is that it is dry-firing after emptying one magazine.

KSC Mk23 SOCOM Pistol CO2 Custom Operation Video

I think I managed to show some pretty good sharpness.

Normal video, same condition, dry firing after emptying one magazine.

KSC Mk23 SOCOM CO2 Normal Operation Video (Caution: Sound)

I think it's improved considerably compared to before, so I believe the customization has had a positive effect.

This concludes the verification of the live-fire performance.

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

Although I had a problem during the customization process where I broke the piston unit and had to rely on KSC's service department, I managed to complete the customization somehow.

Although we weren't able to achieve our initial goal of stabilizing the initial velocity, we were able to achieve the other objectives, so we'll consider it a success.

The customizations have improved the operability and the crispness of the blowback, which is good, but I regret not being able to modify the blowback unit, which is the heart of the gun.

In summary, the custom work was challenging because KSC's unique mechanism means there are very few custom parts available, and my own expertise is limited. It would be helpful if there were aftermarket parts available, such as the inner barrel and hop-up packing.

The unique blowback unit still has plenty of room for improvement in terms of performance and cost, so I think it would be even more interesting if KSC or some third-party company put in the effort to develop it further.

In particular, many of the blowback unit parts are currently manufactured using machining, which limits their shape. However, I hope that as production increases, it will be possible to use manufacturing methods such as lost-wax casting and MIM (Metal Injection Molding) to create more flexible shapes and reduce costs.

I hope KSC will continue to work hard with the 0 system and sell many models, leading to the evolution of their unique mechanisms and a boom in aftermarket parts.

Thank you for your time.

KSC Mk23 SOCOM Pistol CO2 ABS
This is the only gas blowback model of the SOCOM, and I highly recommend it.

KSC Mk23 SOCOM Pistol CO2 27-round Spare Magazine
Up until now, obtaining spare magazines from KSC was quite difficult (past tense). The future is uncertain.

KSC Genuine CO2 12g Cartridges (50-pack)
If you don't have any particular preferences, this isn't the only option (the price is a bit on the higher side). While 50 bottles might seem like a lot, they'll run out quickly. At your own risk, you might be better off with something cheaper.