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· Registered
1 Posts
Discussion Starter · #1 ·
So I'm new to this forum, but I thought I should post this up here to help anyone out.
I've searched everywhere, but couldn't find a complete disassembly thread for the Umarex MP5 A5 in .22LR, so I went ahead and did it myself.
Seeing as how the rifle only cost $500, I don't mind voiding a warranty.
Also, I contact Umarex, as they said they'd be happy to ship me any replacement parts as needed!
Note: Disassemble at your own risk! Your weapon-your warranty.

I'll start with a level 1 disassembly, which allows the owner to properly clean the weapon.

1. As always, ensure chamber is clear.
2. Remove all three push pins, and using supplied compensator removal tool, remove compensator, o-ring, and 3-lug.
Doing so, you will be able to pull out the upper receiver from the upper receiver housing.
This will give you a chance to clean out the upper receiver housing (after 400 rounds, mine was a bit nasty, and field stripping was insufficient)

To remove the internals from the lower housing, remove the allen screw within the pistol grip, and the pin from the right side selector.

Remove the hammer stop pin and hammer retention pin from the case located above the trigger.
This will allow you to slowly wiggle the hammer assembly and spring out of the case. (Inside the case, you will find the spring base)
Remove the four(4) allen screws and nuts.

When separating the housing, make sure to open it slowly, as the safety selector has a springed detent.
The trigger group will stay in place, but the nut for the pistol grip may fall out, as well as the hammer spring base and black bump stop.
The picture shows all parts removed (the trigger springs are a little bit difficult, but can be pulled out & put in using a pick)

To reassemble, do all in reverse, ensuring pistol grip nut, black bump stop, and hammer spring base are aligned.
Congratulations! Take this chance to lube any friction points (I always suggest Teflon based dry-lube)

This is the fun part, becasue you get to see the internal set-up of the HK/Walther/Umarex upper.
The first thing to do is remove the bolt speed adjuster.

When you remove that section, you will have the allen lock, spring, and two(2) spring end caps.

Remove the five(5) sets of allen screws and matching nuts.
The two short ones are from the two slots towards the top.
This will bring you to the picture below, with one side of the housing removed.
Here you can see the empty magazine bolt stop, extractor, barrel, bolt assembly, and two(2) aligned pegs.

Before pulling barrel out, note that there is barrel detent spring & pin that is secured by the empty magazine bolt stop.
So in order, remove barrel, then empty magazine bolt stop PIN, empty magazine bolt stop, then barrel detent spring/pin.

Again, take advantage of this chance to properly lube friction points. My main focus was the areas the bolt slid along upper receiver.

First, remove the rear sight retention screw from up top.
Gently work the rear sight vertically out of its location.

CAUTION: There is a spring, spring caps, and bar for the cocking handle within the upper receiver housing, with a very minimal amount of tension.
Get ready to stop them.
Remove the four(4) allen screw & nut sets

As far as disassembly goes, this should cover 99% of what you need to properly disassemble, clean, & lube your MP5 A5.
I haven't attempted to disassemble the remaining barrel shroud/cocking tube assembly, as it seems near impossible to get the roll pin out of the cocking handle.

Well, I hope this helps a lot of people out there, but remember, it's your warranty to lose.
I've built/maintained many rifles & handguns (even designing a rifle right now!), and this rifle has the most parts I've seen before.

· Merchant of Death (Admin)
12,552 Posts
I have moved this into the proper section. Please fix the picture links, else this post is mostly useless.

1,426 Posts
Here are a few pics to help you figure that 'split' receiver and barrel install... Note the small pin and spring that has to be depressed for the barrel to be installed into the left half receiver piece; this is also the spring that actuates the last round bolt catch lever. Hope this helps...

Gun Firearm Revolver Trigger Gun accessory
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