MP5 Project Build

[Ben Savage]

Hello, this thread is basically to provide a log of what I'm doing for an MP5 project, and to see if anybody has any tips, or information about part compatibility.

 

I recently acquired a boneyard G3 which was included with a bunch of other stuff, and decided to try and restore the gun to working order. From first inspection, I could see the G3 had the stock snapped, the RIS rail held on by a single screw (therefore was really wobbly), the receiver had the front part which holds the barrel snapped off, causing the barrel to bend to the left severely, and the lower receiver had a small part snapped off. There were also some other small issues which could be spotted initially. I then stripped the G3 down, to find the wires had been soldered to the motor, the wiring was not in great condition (and was also wired to large tamiya). The next part of the strip down was to open the gearbox up, which I decided to do at a later date.

 

I made a post on here about whether it would be worth trying to replace these broken parts, or whether to build it into a new gun, and it was widely agreed upon that the condition of the G3 was basically beyond repair, especially given availability and price of parts. Because of this I was effectively left with a motor and a V2 gearbox , which I thought was in reasonable condition to use if I was to buy external parts for a different type of RIF which would have parts easier to obtain than a G3. I decided on an MP5A5 would be a nice 'project gun' and started looking for parts. I already have a TM MP5 High Cycle, and 6 mags so this decision made sense.

 

Now I know that with what was left of the G3 it is completely pointless to try and make a gun from buying parts, when I could just buy maybe a JG or a CYMA MP5 for what would work out (much) less than this is going to come to overall, however given that I have lots of free time still as a result of the coronavirus, and an interest in learning the technical side to airsoft guns better without potentially ruining one of my working guns, I figured this would be a nice project to build.

 

Now because I had decided on an MP5, I started briefly looking for parts, and immediately found on ebay an MP5 lower receiver in perfect condition (damage wise at least, needed a small clean when it had arrived), for just £5 which arrived nice and quickly. The listing didn't give any information about the make of the receiver, but it is identical to my TM receiver including the ASGK marking in the same position, so I'm sure this is a TM receiver.

 

After this had arrived, I finally decided to remove the motor from the G3 lower, so I could then remove the gearbox and inspect it. The G3 was only firing on automatic, which I thought would be down to a selector plate problem, but when i looked at the side of the gearbox there just was no selector plate there, which explains the auto/auto/auto fire selector. Next up was opening the gearbox up, and it was not a pleasant sight inside. The first thing I noticed was a huge squirt of hot glue holding in a micro switch at a very bad angle, with the trigger (which had been cut down, looking very messy). There were so many problems inside of the gearbox, that the only parts that I considered to be usable again were:

• Gearset (Had JG markings, all but confirming the unknown manufacturer of the G3 to be JG)
• Piston
• Cylinder
• Spring
• Spring Guide
• Tappet Plate
• Anti Reversal Latch

I then noticed cracks forming in the already radiused gearbox shell, and this may be an over reaction, but decided that the very small cracks were reason to scrap the gearbox shell, and replace this as well.

 

Now that I had decided the gearbox shell would need replacing, it would have made sense to call the project off because it is essentially from no parts now that I'm building this, but I was in need of a project so I decided to continue. So ordered an E&C gearbox shell with QD spring guide, as I had heard good things about these and considered the price to be reasonable. The first thing I did when this arrived, was test that it actually screws in to the lower receiver, which it did, so the next step is to make a shopping list of parts that will continue the project, and try and get information about compatibility from people who know more than me. I also ordered a set of MP5 gearbox springs, which will be useful for the selector plate and trigger switch assembly.

 

Parts Owned:

• Lower Receiver
• Gearbox Shell
• Spring Guide
• Gear set
• Piston
• Cylinder
• Main Spring
• Spring Set
• Anti Reversal Latch
• Shims
• Tappet Plate

 

Internal Parts to buy:                                              [Total = £41.50]

• V2 Cylinder Head - https://www.ak2m4.co.uk/internal-parts/cylinder-heads/ra-m4-cylinder-head-silent - £6.50
• MP5 Nozzle - https://www.fire-support.co.uk/product/lonex-mp5-a4-a5-sd5-sd6-series-air-seal-jet-nozzle - £8.00
• MP5 Selector plate - https://www.fire-support.co.uk/product/lonex-anti-heat-selector-plate-for-mp5-series - £9.00
• MP5 Trigger - https://www.fire-support.co.uk/product/ultimate-reinforced-trigger-for-mp5-series - £8.00
• V2 Switch Assembly - https://www.ak2m4.co.uk/internal-parts/trigger-switches/ra-trigger-switch-v2-red - £4.00
• V2 Cut Off Lever - https://www.ak2m4.co.uk/internal-parts/cut-off-levers/ra-cut-off-lever-v2 - £3.50
• V2 Safety Lever - https://www.ak2m4.co.uk/ec-safety-latch-v2?search=safety - £2.50
• Inner Barrel - Included with Upper Receiver Set
• Hop Up Unit - Included with Upper Receiver Set
• Wiring - 
• MOSFET - Perhaps GATE MERF? - Recommendations welcome

 

External Parts to buy:                                            [Total = £79.00]

• MP5 Upper Receiver set - https://www.fire-support.co.uk/product/ics-a-series-complete-upper-kit-for-mp5 - £79.00
• MP5 Motor Base Plate - 
• MP5 Collapsible Stock - 
• MP5 Fire Selector - 

 

Hope to keep this up to date with changes that take place, and if anybody has any part recommendations, (especially for parts not yet listed) it would be great, and any feedback will be greatly appreciated as well. Photos will also be added eventually, as this begins to take shape.

[PopRocket123]

Snap. I swapped an old pistol for a box of bits containing most of an MP5 as a practice project. It's a mix of parts, some of which need some modifications to fit together. I recommend putting together a hop and barrel set up that you know is reliable and won't jam, putting the upper receiver and barrel assembly together and then leaving it the hell alone. It's such a pig getting all the wiring and screws in and I always feel like the threads are going to strip. 

[Shamal]

PopRocket123

Like a Phoenix from the ashes👍

[PopRocket123]

1 hour ago, Shamal said:

PopRocket123

Like a Phoenix from the ashes👍

Not quite. Right now it's more like a zombie rising from the dead.