"Multiplefeeds" with Madbull ultimate hopup
 

I've installed a Madbull ultimate hopup on one of my uppers (G&G M4 full metal), and most of the time it shoots well, however from time to time it "multiplefeeds" (ie 2, 3 bbs at the same time).

Any idea what can cause this?

(Nozzle is the stock non-cansoft G&G)

EDIT: Tested with both my DBoys lowcaps and my G&P midcaps. It does the same.

which rubber did you use? is the nozzle the correct length?

take the madbull hopup and the stock hopup unit and measure them side by side and see if one sits more forwards than the other.

Prometheus with SCS nub.

I'll do it...

EDIT: they seem to sit at pretty much the same place

EDIT2: Tried my other upper (different hopup+barrel assembly) and it just doesn't feed... probably my nozzle or tappet plate I guess. The nozzle does move... but it seems to not go far enough.

The only problem I had with my Madbull ultimate hopup was it would feed sometimes and other times it would not.

I had discovered that the Deep Fire Metal Nozzle was slightly to long, so I shaved it down a couple mm and now it feeds perfectly.

As for feeding to much, well I'm sorry as I did not have that issue.

put a bb in the feeding tube, grab a screwdriver and press the off-center of it gently to see if it pushes forward into the hopup, it should but it shouldn't do it easily enough that BBs in your magazine can push more in.

Hehe.

I've not had this issue with it myself though :P

Considering it doesn't feed at all (nozzle isn't going far enought) in my other hopup/barrel assembly, it's most likely the nozzle and/or tappet plate and not the hopup... ill check that later.

I can bring you an extra Modify nozzle if you wish to give it a try :P

But I swear, that hopup is damned :P

Yea, I'm not a fan of much Madbull stuff.. and their new hop-up is no exception.

haha, +1, that why all my local guntechS (yes all of them) dont recommend it...lol
because of the feeding issues .....

Madbull Hop Up is a great unit. Inner barrel with hop up rubber is tricky to put in but if you get it right you'll be happy how it performs.

*edit add*

You put the barrel with the hop up rubber wrong yes its either it will not feed or it "multiple" feeds. Installed 3 hop units from clients guns. All are happy with the performance.

The madbull hopup is working great for me. Only suggestion is that if you use it with the madbull tight bore barrel, you should use the supplied madbull rubber. (not sure about the new version inner barrels though)

Take out the SCS nub and try it.