MAGPUL PTS MASADA ACR CQB Disassembly Guide

This time, we'll be disassembling the MAGPUL PTS masada ACR CQB.

If you're interested, please also check out the review section.

Let's start disassembling it right away. First, we'll remove the outer casing.

Disassembly of the exterior

Removing the handguard is the same process I described in the review section regarding the battery, so I will omit the explanation here.

First, set the hops to 0.If you don't do this, when you remove the barrel, the hop-up bucking will remain pressed against the packing, which can be dangerous.

Next, return the port using the bolt release lever, then remove the barrel. It's easy with the quick system. Raise the handle and turn it counterclockwise to remove it forward.

The rust is quite severe, but I'll accept it as proof that it's made of iron.

I'll leave the removed barrel as is for now. Incidentally, it has a gas operation rod attached, which is unnecessarily elaborate. The regulator is also functional.

Next, return to the main unit and remove the two pins at the rear end of the receiver. There is no retaining mechanism, so they will come out completely.

By the way, in the past, we used to remove the pins with a hex wrench (it was somewhat usable), but it bends and is difficult to use, so if you're considering disassembling or reassembling it, it's easier to use a punch.

I use a punch from Signet (which I think is common in the motorcycle and car industries), so I'd like to recommend it. It's inexpensive but of good quality and is a favorite among professionals.

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.

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

Also, it's better to have a base when removing the pin.

A loose pin got stuck in my thigh. And it made a hole in the carpet.

I use Eagle Model's handgun maintenance stand. Even though it's designed for handguns, it works perfectly fine for longer firearms as well.

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.

Once the pin is removed, the upper receiver will open. Remove the front pin as well and then remove the upper receiver.

Next, remove the stock. It's simply fitted into the lower receiver, so you can remove it by lightly tapping it upwards.

Next, remove the bottom cover of the grip. For some reason, it's held in place by two hexagonal screws of different sizes.

That completes the basic exterior work. I don't think it took more than 10 minutes. Amazing.

Barrel, chamber area

Remove the inner barrel and chamber from the removed barrel and upper receiver.

First, for the chamber, use a punch to remove the two hex bolts on each side of the upper receiver (there are also some on the other side) and the two cotter pins.

This will allow you to remove the chamber assembly. Once you remove the hex bolts, you can remove the chamber containing the gasket.

Luckily, my unit didn't have any looseness or rattle here. I've heard rumors that it's quite loose and doesn't seal properly.

The chamber can be removed.

Next, remove the inner barrel. It is secured to the base of the removed outer barrel with a grub screw. The inner barrel will pop out due to the spring pressure, so be careful not to lose the grub screw.

This is a complete inner barrel assembly. The tip of the inner barrel had a tapered design.

That concludes the barrel assembly.

Next, we'll remove the gearbox.

Gearbox extraction and disassembly

Remove the two Phillips head bolts inside the magazine housing of the lower receiver.

Set the selector to semi-automatic and pull the gearbox straight up. Below is the gear for the ambidextrous selector.

Let's take a look at the gearbox. It has an ambidextrous selector gear.

The motor and switch wiring are all firmly soldered together.

Now let's remove the motor holder and take a look at the gearbox. It seems to have 8mm bearings and plenty of tightening bolts, which is good. It's a pain to assemble, but the high tightening rigidity is a good thing.

While you're at it, take some time to remove the spring using the QD tool.

　Now, let's open up the gearbox.

Compared to other products of that era, the amount of grease applied was rather restrained, which I appreciated. However, for some reason, it was drenched in an oil that resembled engine oil. It's good for lubricating bearings, though.

Next, let's take a look at the individual components inside the gearbox.

Parts inside the gearbox

Now let's take a look at each component.

Gearbox casing

The workmanship is relatively clean. The 8mm bearings and the generous number of screws securing the spine are also positive points. However, there's no protection against gearbox cracking. It can be used with a little modification.

Switches, motors

The switch is a microswitch from an unknown manufacturer. It needs to be replaced.

The trigger area has an unfamiliar shape due to the use of a microswitch.

The motor is a short, unbranded, mysterious motor, so it needs to be replaced. The wiring is also thin, probably 0.75 sq. The pinion has a fairly wide tooth surface, so the noise should be reduced depending on the settings.

Intake and exhaust system

This is the cylinder head. It appears to have a double seal for good airtightness. There's a rubber plate on the bottom. It seems like a pretty good part. The nozzle is long.

Next is the nozzle. It's a double-seal sealing nozzle. It fits the head without any particular tightness, so it's usable.

Next is the cylinder. It's a full-size stainless steel one. The air volume isn't suitable for this barrel length (318mm), so it needs to be replaced.

Next is the piston assembly. The piston head wouldn't come off. The head is a two-hole type with rear intake. The piston is made of polycarbonate, with only the last tooth being metal, and the second tooth was missing at the beginning of the gear engagement. It should be replaced at the polycarbonate stage. There was a thrust bearing installed to compensate for spring twisting.

Finally, the tappet plate. I like the shape of the blades, which have a rounded base. I think the other precision parts are also good. By the way, Ver.2 can be used almost as is.

drive system

Let's start with the sector gear. The tappet cam has an odd shape. It's interesting that the tappet cam is press-fitted. The quality is average, I guess. Only the last tooth is thicker.

Next is the spur gear. It has a collar. It's not a very nice collar. It's much better than the spring shim, though. The quality is just average.

Finally, there's the bevel gear. It's quite challenging because it only has four anti-reverse latches. It's fine at the stock cycle, but increasing the cycle speed could lead to overrun. The quality is just average.

Other Information

This is an anti-reverse latch. I still can't really tell the quality of a part just by looking at its shape. I wonder if I can tell if it's poorly made just by looking at it?

This is a spring guide. It's incredibly light. It might even be made of aluminum. It even has a thrust bearing to prevent the spring from twisting.

Finally, the cutoff. It has an unusual shape. There doesn't seem to be a suitable replacement, but it probably won't break.

That's all we have.

Summary and future direction

In summary, the parts used seemed to be top-of-the-line for their time (around 2015).

In my unit, simply replacing the packing and spring was enough to make it work perfectly. I didn't experience any issues with the hop-up not working.

It's incredibly easy to assemble and disassemble. It's the best I've ever used. With practice, you might even be able to completely disassemble the gearbox in about 15 minutes.

However, it does have some drawbacks; at its current level, the response and cycle time are quite slow. We will improve these aspects.

Also, I recently happened to find a Ronex A3 motor medium on sale for half price, so I'll be using that as the base for my setup.

In the end, it looks like it will be a high cycle rate of around 25 rounds per second again. (Ideally, it would be around 22 or 23 rounds per second.)

In some cases, since there is ample space for the battery, we might incorporate any interesting multi-functional MOSFETs if we find any.

In any case, the next episode will be about customization. Stay tuned to see what happens!

Also, for those who already own a Masada or are considering purchasing one, only used ones are available, so please use this to compare parts and determine the production lot of the item you are considering.

My Masada has a lot number in the 10000s, and I acquired it towards the end of the production run, so I think it's probably close to the final batch.