Intermittent Double feeding with fps drop

[garvey2003]

Hi,

Hope someone can help me out on this one. I have a G&P M4 which has been upgraded with

ASHU Hup-up Unit
ASCU2 trigger/mostfet
ASG Ultimate Gearbox
ASG HI
ASG Tightbore

The Problem:
every 5-7 shot it will either double feed or drop fps by 100 and sometimes both.
If I spam the trigger on semi then all seems to fire ok, when I fire semi or three round bursts normal or taking my time then I get this issue.

The gun was firing too hot so had a tech sort it for me, now the fps is around 340. the tech told me the reverse latch is not installed but would expect that if I run 11.1 lipos which I do.

Any suggestion would be great as im starting to give up on it which is shame as its favourite bit of kit at the moment.

thanks
Paul

[sj_asc]

Re: Intermittent Double feeding with fps drop

Not nescessarily related to the cause of the sealing issue, but i would throw some suspicion at the explanation given as to why there is no AR latch.

Firstly to help diagnose the problem;
* Is the sealing issue with certain mags?
* Is it more prominent when the mags are full or fully wound?
* Is the issue also consistent with heavier weights?
* Is there play in the mag seating? If you movbe it about when firing does this affect the sealing/fps consistency?
* Is the hop chamber sufficiently spring against the front of the gearbox?
* Is there any excessively tight fitment with the chamber?

Internally;
* The ASG Ultimate Gearbox and internal parts are OEM'd by Lonex, Are all of those parts present or is it a bit of a Pick'n'Mix? (exclude the ASCU)
* What hop bucking are you running?
* Have you tried with a different chamber?
* Is there any distortion to the hop bucking sealing lips?
* If you stall the gearbox so that the nozzle is at rest check that;
- The Nozzle can be pushed in and springs back to position smoothly
- There is not excess lateral play in the nozzle at this position.

In addition to this, I would suggest installing the AR latch. Failure to do so can result in serious damage to the tappet plate which if sustained will cause feeding failure, or potentially worse if the tappet fin breaks loose into the gear train. If there are timing issues that are related the cycle completion function of the ASCU and the AR latch being used at higher cycle rates, then they need to be fine tuned out rather than being bypassed by with a shortcut that could lead to other potential problems.

[garvey2003]

Re: Intermittent Double feeding with fps drop

* Is the sealing issue with certain mags? No I Have tried lots of different mags, makes and sizes
* Is it more prominent when the mags are full or fully wound? same happens when mages are full, half and almost empty
* Is the issue also consistent with heavier weights? tried 0.2,0.25 and different brands but still happens
* Is there play in the mag seating? If you movbe it about when firing does this affect the sealing/fps consistency? all the mags have a little movement but if wiggled doesn't change the effect
* Is the hop chamber sufficiently spring against the front of the gearbox? Yes it does have a spring
* Is there any excessively tight fitment with the chamber? I assume you mean hop to chamber, all seems fine

Internally;
* The ASG Ultimate Gearbox and internal parts are OEM'd by Lonex, Are all of those parts present or is it a bit of a Pick'n'Mix? (exclude the ASCU) All the internals are ASG apart from the ASCU as you mentioned
* What hop bucking are you running? Not sure which one it is as was already fitted, blue is all I can say
* Have you tried with a different chamber? No I haven't as I don't have access to another hop unit
* Is there any distortion to the hop bucking sealing lips? All looks as it should
* If you stall the gearbox so that the nozzle is at rest check that;
- The Nozzle can be pushed in and springs back to position smoothly Yes it can
- There is not excess lateral play in the nozzle at this position. no play

Thank you for taking the time to try and help me. the AR latch was removed not by me and was told it doesn't need to be in the gearbox as I'm running 11.1 lipos.
Think I will get a latch fitted and also see if I can borrow another hop unit to see if that helps.

thanks again
Paul

- - - Updated - - -

Oh I will add, I did buy a Prowin but it didn't fit, once installed if put it together without the front pin on the receiver it would fire but as soon as I put the pin it wouldn't feed. seemed it didn't like the upper G&P receiver I have fitted.

think I will order a G&P hop unit to try

thanks
Paul