G&P XM177E1 AEG Exterior Disassembly: Gearbox Removal

Last time, I gave an unboxing review of the G&P XM177E1, so this time I'll be showing you how to disassemble it.

The delta ring spring used to remove the handguard on this product is extremely stiff, so we will also disassemble the front end to address this issue.

First, we'll start by disassembling the front section.

Disassembly of the front and outer barrel area

First, we'll remove the distinctive flash hider.

Please note that this is a standard thread, not the industry standard reverse thread (turn counterclockwise to remove).

Hider

By adding a 1.5-inch extension barrel to this part, or by changing the barrel itself to an 11.5-inch one, you can convert it to the E2 specification.

Next, we'll remove the Delta Post (front sight and gas tube).

First, remove the pin at the location shown in the photo.

The pin circled in blue is the pin that secures the gas tube, so you don't need to remove it.

Incidentally, airsoft guns use a lot of pins, so it's convenient to have some sturdy tools. You can technically remove the pins using cheap tools, hex wrenches, and hammers, but it can be difficult and may cause damage.

Therefore, I'll list my recommended tools at the end of this front disassembly guide.

Once the pin is removed, the next step is to remove the swivel. The swivel is held in place by the pin shown in the next picture; remove it by pulling it out.

Next, remove the grub screw hidden on the back of the swivel. Be careful when removing it, as it is quite stiff.

Once disassembled to this extent, the front sight and gas tube assembly can be removed by pulling them forward.

Next, remove the outer barrel. M16 and M4 series rifles are secured with special nuts, so you will need the following tools.

While hook wrenches and special tools for M16 and M4 series bolts are sold by various companies, this heavy-duty one is my top recommendation.

I've bought several tools of this type myself, but this is the best one. The only drawback is that it's heavy, but since I don't usually carry it around, it's not much of a problem. I'll introduce this at the end of the front disassembly section.

Returning to the disassembly process, align the grooves on the tool shown in the photo with the grooves on the delta ring and rotate it to remove it.

It was incredibly stiff, and I couldn't remove it. We tried heating it up, thinking it might be threadlocker, and even with two people trying to turn it, it wouldn't budge, so we gave up.

While struggling to remove the outer barrel, I came up with a way to reduce the spring load of the delta ring without having to remove it, so I decided "it's okay if I can't remove it."

I'll explain how to do that in the customization section. If you absolutely want to remove it, I think you can manage it if you have a fairly sturdy vise.

This completes the disassembly of the front section.

Here are some recommended tools (I come from an automotive engineering background, and based on my experience, I recommend Signet and Vessel as cost-effective tool manufacturers).

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.

- No-brand multi-tool for AR15
This is a multi-tool for M16 and M4 rifles. With this, you can service most M4-type rifles from most manufacturers. It's bulky and convenient, but it's heavy.

Next, we'll remove the gearbox.

Removal of the upper receiver

We'll start by removing the upper receiver, a standard component for M16 and M4 series rifles.

Remove the front pin.

Since it's front wiring, disconnect the wiring before removing the upper receiver.

The wiring is protected at the joints with heat shrink tubing, so you can cut it with wire cutters or similar tools.

Now, move the upper receiver forward and remove it.

This allows you to separate the upper receiver, hop-up chamber, bolt cover, and lower receiver.

Let's take a look at each of the parts here.

This is an upper receiver.

The barrel has a metal component pressed into its base, making it quite robust. This suggests it will have excellent accuracy.

Next is the hop chamber.

It's made of cast aluminum and has airtight resin parts, so it looks quite good. The positioning spring is also just the right strength, which is nice.

I think I'll use this as is.

Next, let's look at the hop shape when the hop is at its maximum.

It's not a special shape or a long-acting hop; it's a very ordinary type.

Next, we will proceed with disassembling the lower receiver.

Disassembly of the lower receiver

The first step in disassembling the lower receiver is to remove the magazine catch.

G&P models, like Tokyo Marui standard models, have a screw on the magazine catch, so you need to remove it.

Once you remove the screws, you can remove the parts related to the magazine catch.

Next, remove the pin on the back.

Next, we'll remove the grip.

First, remove the bottom of the grip. It's held in place by two hex bolts.

Once the bottom is removed, the motor becomes visible.

First, you need to disconnect the motor's wiring, but it's secured with screws instead of the usual faston terminals. Disconnecting it is a bit of a hassle, but I think screw fastening is the correct design choice.

Let's take a look at the motor that was removed.

I thought it would have an M120 motor, but it turned out to be a more mellow M100. It's a decent one, though.

Let's take a look at the pinion gear, which is significantly related to noise. It appears to be manufactured by machining and likely has good precision (unlike Lonex, which uses forging).

Next, remove the grip. The grip is attached to the gearbox with four screws. Usually there are two screws, but I like that there are four, as it seems to provide more strength and precision (although it's a pain to remove).

Now you can remove the grip.

The final step in disassembling the lower receiver is to remove the thin pin located near the trigger. Pay attention to the orientation of this pin, as it has a specific direction in which it should be removed.

This should allow me to remove the gearbox, but I couldn't remove it from the G&P model. It turns out the gearbox and stock pipe were screwed together and fixed in place.

This is great for performance because the gearbox's position is fixed and secured, but it makes removing the gearbox a hassle.

Therefore, we will disassemble the stock pipe in order to remove the gearbox.

Disassembly of the stock tube and removal of the gearbox

Remove the stock. It can be removed using the same procedure as a typical telescopic stock.

Once the stock is removed, the stock pipe will be exposed. Remove the hex screw that secures the cap at the rear end of the exposed stock tube.

The lid can be easily removed by unscrewing it.

Looking inside the stock pipe through the removed cover, you can see the Phillips head screw that secures the stock pipe to the gearbox.

The bolt inside this stock pipe is quite tricky to access; you'll need a fairly long screwdriver to reach it. Since the stock pipe is over 170mm long, you need to be careful to have the right screwdriver ready.

I use a Vessel screwdriver with a +2 size and a 300mm extra-long length. I'll introduce it at the end of this section.

Going back to the disassembly process, once this screw is removed, the stock pipe can be detached.

Now, turn the receiver on its side. This will finally allow you to remove the gearbox.

This will reveal the gearbox.

Since this is a good stopping point, I'll end the introduction here for today.

Vessel Extra Long Ball Grip Screwdriver
The screw size I use is +2 sizes larger and 300mm long. This will fit most stock pipes.

Summary

This time, we mainly introduced the disassembly of the exterior.

My impression of the exterior parts is that each one was made very solidly and carefully. The design of the exterior parts was also quite elaborate, and I'll list some of the good points that caught my attention.

I was impressed by the robust structure of the outer barrel, and especially by the way a metal part is press-fitted into the upper receiver to secure the outer barrel.

Other notable features include the hop-up chamber being made of cast aluminum and having a resin part for airtight sealing. Furthermore, I appreciate that the positioning spring for the upper receiver is not small and weak, but rather a fairly thick and strong spring.

The last good point is that the gearbox is screwed to the stock pipe to ensure it's centered in the receiver. This should have a significant positive impact on accuracy as it ensures the gearbox is properly centered.

Next time, we'll disassemble the gearbox and consider the direction of customization.

Please come along if you like.

This is a highly recommended product, but it seems that it hasn't made much of an impact on Japan, perhaps due to the effects of the coronavirus.

Therefore, I'll introduce some models that are in stock at the time of writing and that I personally like.

G&P AR 9mm SMG AEG
A US military SMG from the Vietnam War era. The M16 receiver combined with the oddly sized 9mm magazine looks really cool.

G&P M16 Vietnam Version
This was a mainstay rifle from the same period as the XM177 series.

G&P M4A1 AEG Marine Corps Model
定番です。