[How-To] APS Phantom Extremis MK7 MPX CQB Takedown, disassembly guide

This article shows you how to disassemble the APS manufactured Sig MPX gel blaster. From this point forward, we will use the term MPX to identify the gel blaster rifle and all of the variants (Titan SBB, Titan LBB).

Suggested Tools
2mm Hex Key
2x 4mm Hex Keys
Philips Screwdriver
Flat Screwdriver

Separate the Upper and Lower Receivers

The receiver is the main body block at the centre of the MPX. The receiver can be separated into two: the upper and lower receiver. The upper receiver is the attachment point for the front rail/handguard, the external barrel, the inner barrel, suppressor, etc. The lower receiver carries the gearbox, the rear shoulder stock, motor, and handgrip.

To separate the receiver, use the 4mm Hex keys on the 2 receiver pins. Located at the front of the receiver, right under and behind the rail/handguard. Use a hex key on either side and unscrew. It was a snug fit on the front one, requiring a bit more of force to tap it out.

Once the receiver pins have been completely tapped out, you can slide the upper receiver forward, while pulling the lower receiver backwards.

Removing the Handgrip
The MPX uses a v2 gearbox, so the handgrip is attached to the bottom of the gearbox and houses the motor. The base of the handgrip has a plate with two small screws. The big flat screw in the middle is to adjust the motor tension to the gearbox. Using a Phillips screwdriver, unscrew the two small screws to remove the plate.

After removing the handgrip base plate, you’ll see the motor and attached wires. Detach the wires and remove the motor.

Next step is to remove the handgrip. There are two screws inside the motor housing. Unscrew the two screws with a Phillips screwdriver. Be careful that the screws don’t fall into the gearbox. Once you’ve unscrewed the handgrip, you can remove it easily.

After removing the handgrip, you’ll see the bottom of the v2 gearbox. What do you know… there are actually 4 screw holes!

Separate the Gearbox From the Lower Receiver
To separate the gearbox from the lower receiver, you’ll have to tap out one receiver pin. I used the 2mm hex key and a rubber mallet. The receiver pin is just forward of the selector switch. The photo below shows the receiver pin half tapped out.

Next, remove the magazine release. With the right side of the receiver on top, use a 2mm hex key to unscrew the magazine release button. Be careful you don’t lose the spring under it.

For ease of removal put the selector switch into safe ‘No Pew’. Then remove the selector switches with the 2mm hex key. Unlike your typical M4 this has to happen as they are slightly recessed into the APS Silver Edge box for the ambidextrous gearing.

Be super careful not to lose the small ball bearings which give that tactile ‘click’ as you select fire modes. They are held in with a spring so just hold down the switch and unscrew it on a level bench etc.

By this stage, the box can move around a bit in the receiver. To remove the bolt catch mechanism. Pull the gearbox out of the receiver slightly until you have revealed the latch. Flip the receiver over to the left side. The latch is held in place with a split pin, I used the 1.5mm Hex (or a similar diameter punch) to tap it out towards the front of the MPX.

It took a bit of wiggling but the latch pulls out of the receiver, freeing up the gearbox to be removed. The selector gears are freely moving around and there is a good chance they will drop out as you remove the box from the receiver.

This is a work in progress, I’m saving it all as I go!

7 Likes

Fantastic take down guide.

Have you looked at how to swap out the stock with a buffer tube?

I’m on the fence about the PDW style collapsible stock, and want to know how to go about swapping it over if I ever decide to do it. I’m imagining an armourers wrench is required, and from what I’ve gathered online, the gearbox has to come out first anyways.

I hadn’t gotten that far but @Maystro has.

Yep Gearbox has to come out.

Sweet. Will definitely be keen to see what’s involved in getting the PDW stock off and a buffer tube in place (and what buffer tube works best).

You can just undo the nut with little holes in it , it’s in the receiver end of the battery compartment. , no need to remove the gear box.
You can see this post from @Maystro

1 Like

I dont have one of these but have to post to say well done on a brilliant how to. Kudos to you.

1 Like

Cheers. It would be awesome to see one of these for every model out there.

1 Like

No, we don’t want that :anguished:

Then there would be no spending hours trying to work out how to dismantle something, assemble something, have tiny springs or screws fly out of somewhere never to be seen again, or do the old “one step forward, two steps backwards” when you’re trying to get something apart or back together.
And the favourite - having just assembled something and thinking that you have done really well. Then you spot the small spring / screw left on the bench, and think Where The F### did that come from? Did I leave it out? Is it from something else? Don’t tell me I have to pull this apart again?

Seriously though, a very good how-to. Well done :ok_hand:

3 Likes

Don’t worry @HelterSkelter that is just the disassembly.
As you know the fun times are when we try and put all the bits back together and improve on our blaster and make sure their is no air leaks and extra parts :joy:
We need to keep our big Leader @BigWeetBix honest and make sure he can show us some of the trade secrets since he is always mingling with the manufacturers :wink:

2 Likes

If this is true then where are the special deals for forum members ?

1 Like

I’m sure @BigWeetBix is talking to the many Gel blaster business’s right now, like Max, Sam and Brent, (sorry I don’t have any more names to drop) about some great deals for us right now. You know using the power of bulk buying to get some good deals for the loyal forum users :grin::innocent::sweat_smile:

1 Like

Yippy, that is really great news !
Thanks for the heads up @Maystro
I am quivering in anticipation :raised_hands: