KWA MP9 disassembly

[amateurstuntman]

I had to replace a sear in my MP9 so I thought I'd do a quick guide.

I had previously done one for the TMP but the pictures are down due to my image hosting website folding - nice one Village Photos.

 

All pictures are clickable thumbnails.

 

You must first field strip the MP9 and for the sake of completeness I will show that process first.

 

Field Strip.

 

Remove the screw from the front of the upper receiver:

 

You can get away with leaving it in but over time you will damage the screw and the screw hole and crack the front of the upper receiver.

 

Next, press in the button at the rear of the upper receiver and lift the whole upper off the top.

DO NOT hinge it forward, you can damage the upper receiver by doing it that way.

 

Remove recoil spring and guide rod from weapon by pushing forward.

This may already be loose due to removing the upper receiver.

 

Push forward the spring loaded tab on the barrel lug and remove the barrel pin by pulling upward.

DO NOT force it or try to rotate it, it comes straight up and out.

 

Pull down the take-down tabs on both sides and push the bolt forward until there is no gap between the bolt and the barrel lug.

 

Lift the entire barrel/bolt assembly straight up and out, the barrel, barrel lug, bolt and bolt stop/feed ramp come out as one unit.

 

You now have the weapon field stripped.

 

Reassembly is the reverse except you must remember to push the sear forward so that the bolt can drop down into the weapon.

 

 

Now that you have field stripped the weapon you can strip it all the way down.

 

We'll start with the bolt, you will need to do this to replace the rocket valve.

 

Bolt Strip.

 

Start by tapping out this pin.

It is easier to tap it out right to left due to the knurling.

If yours is reluctant to come out it may be knurled on the other side.

 

Beware of the little spring in the second picture, if it pings out it will be tricky to find, keep your thumb over it and try to push your pin drift all the way through (as in the picture) to retain it.

 

Then you need to tap out two more roll pins to be able to pull the cylinder and piston assembly out to the rear.

 

Exploded view of rear of bolt:

 

To get the rocket valve out, just tap out the push pin in the nozzle.

 

Exploded view of the nozzle:

 

Reassembly is the reverse, nice and easy.

 

 

That leaves us with the guts of the thing.

 

Hammer Mechanism.

 

To get the hammer mechanism out you will first need to remove the trigger bar which is held in place by the rear body pin which is retained by a C clip.

Pull out the C clip and then tap the pin through.

 

Remove the trigger spring.

 

Remove the trigger bar retaining block.

 

Squeeze the trigger and trigger bar together and lift the trigger and trigger bar up and out.

 

Next comes the hammer mechanism itself.

 

You need to remove the two forward push pins, one of which is indicated in the pictures below.

They are retained by two of KSC's lovely 0.89mm allen grub screws.

 

Remove them and then pull out the pins, they are a tight fit so be patient and don't smash up the gun.

 

Once they are out the Hammer assembly will come right out. It is another tight fit, be patient.

 

Look for these screws, they remove the recoil buffer.

 

Then you undo these two (one on each side) that hold the mechanism together.

 

Once they are out you can gently prise the mechanism open and remove the hammer and valve knocker assemblies.

 

Hammer assembly is just three parts, easy.

 

The valve knocker assembly is a little more complex, 7 components (one of which is a sub-assembly with 4 components that you shouldn't need to dismantle unless a part of it is broken) all built around a single push-pin.

Make sure you know how the parts fit together before you split them up by tapping the pin out.

 

Exploded shot of valve knocker assembly.

 

Last you remove the sear, to do so you remove the sear spring.

 

Then the tiny C clip - be careful not to loose it.

 

This is why I had to do all of this in the first place:

 

Oops.

 

 

 

Give it a good old clean, reassembly is the opposite.

 

Good luck.

 

Any questions, just let me know by PM or post here, I have subscribed to this thread.

[amateurstuntman]

This is the missing picture.

 

Sorry, I messed up

 

[Flanbix]

Great work! I am feeling a bit more confident now if I have to dismantle the hammer mechanism.

 

You can also add the magazine stripping part to complete this tutorial.

[amateurstuntman]

Go for it, if you run into trouble let me know, happy to help.