JG MP5 Hop Up

[ieuanam]

looks good to me. I can see that it runs parallel to your receiver so thats one less issue to worry about



nice 

 

[ieuanam]

Okay, So I have completely rebuilt the gearbox and it runs good however I had a problem with the piston tooth on the SHS 14 Teeth Piston with teeth 1 and 2 getting stuck with the SHS 13:1 sector gear. I resolved this by short stroking the teeth on the piston.

The problem I have with the bbs dropping is still here but a lot less. In Semi I get 150 fps and the occasional 250 fps with the 250 fps flying how it should.

Go into full auto and thats another story, I'm getting 250 fps with every shot and all the bbs fly out how it should but with the occasional 1 bb going straight to the floor.

I have no clue what is up, I might change the spring to a harder one that I have laying around, I'll try the compression test.

I am thinking that it probably is a barrel/hopup issue and I don't know how to test to see if it is a hopup problem.

@sjhirst Have you fixed your MP5?

 

[sjhirst]

Hi.

No its all sitting in a parts box lol.

 

[Asomodai]

Okay, So I have completely rebuilt the gearbox and it runs good however I had a problem with the piston tooth on the SHS 14 Teeth Piston with teeth 1 and 2 getting stuck with the SHS 13:1 sector gear. I resolved this by short stroking the teeth on the piston.

The problem I have with the bbs dropping is still here but a lot less. In Semi I get 150 fps and the occasional 250 fps with the 250 fps flying how it should.

Go into full auto and thats another story, I'm getting 250 fps with every shot and all the bbs fly out how it should but with the occasional 1 bb going straight to the floor.

I have no clue what is up, I might change the spring to a harder one that I have laying around, I'll try the compression test.

I am thinking that it probably is a barrel/hopup issue and I don't know how to test to see if it is a hopup problem.

@sjhirst Have you fixed your MP5?

Are you using mid caps or high caps?

 

[EDcase]

Fitting a stronger spring would be a bad idea as that would likely break something.

If the hop unit is out of alignment that could explain those inconsistencies.

What about filing the hopup attachment holes in the direction to counter the incorrect angle.  Hard to explain but make the holes longer so the hop can be rotated a bit until the screws are tightened (maybe with some blue locktite)

 

[ieuanam]

high caps

I only have the original high cap that comes with it

If the hop unit is out of alignment

When I get the chance, I will open the gun yet again and send a picture of the alignment.

I mean, with the hop, if you select any setting apart from 1 setting to the back, you will get jams, which I dont know why. The gun just jams

 

[EDcase]

Does sound like the nozzle getting jammed in the hop.

 

[ieuanam]

nozzle getting jammed

I mean, it was doing it since I got it stock, maybe the hop unit is placed too far back on this batch?

 

[EDcase]

Probably would have been best to request a return to be honest.

Open it up and see how it all fits together in one side of the body to check alignment.

 

[ieuanam]

Here is me firing it to show you what is actually happening

View attachment 47377

 

[ieuanam]

@EDcase @sjhirst this is what's happening, does this happen with yours SJ?

 

[EDcase]

Doesn't seem that bad from the video.

Many guns will have occasional BB drops.

I can't help with the difference between semi and auto.

Might have to send it to a tech...

 

[sjhirst]

Yep, thats pretty much what was happening to mine before i took a look inside.  Big variance in fps so knew there was something wrong even before trying to install a jack into it.

 

[ieuanam]

Fixed it, it needs a new bucking and nub and needs to be Teflon taped for better airseal, clean the barrel and boom, works