M4 Not feeding

[VoidSuicide]

I'm having issues with my m4 not feeding properly. To start off, the problem is not the mags, as all the mags I have work just fine in my m16. So the problem is something with how the stuff all matches up. Last weekend I partially fixed this by putting a new spring in between the hop up and the receiver/barrel. however it has not fully remedied the problem. Anyone else have any ideas? And the problem doesn't seem to be just the receiver, as holding it in helps, but it's still temperamental.

[blackout]

take a direct shot over the hop up and see if the air nozzle is seeable through the feeding hole.

[VoidSuicide]

Actually, yes I can right now. I take it that shouldn't be the case, right?

[blackout]

it would probably be causing it to not feed, but its likely this isn't the problem.

[VoidSuicide]

Then what would it be? The entire problem is that its very temperamental about feeding and typically doesnt like to feed.

[blackout]

Is that one piece hop up new?

[VoidSuicide]

No idea. I bought the gun pretty much as is from MCG a couple months ago.

[Rev]

Is your bucking or nub in wrong? I know it sounds silly I had the same problem then I realized I had installed them backwards.

Also I know you said the mags work in a different gun but have they always worked in this gun?

[VoidSuicide]

I honestly don't know. I've not had the gearbox apart, and I've never looked at either of those parts out of a gun.

[SteevoLS]

First: Try different brands of magazines.
Second: If the air nozzle is not completely retracted from the hopup unit when the gun is not being fired, it won't let the BBs feed consistently. If that is the case, you could remedy the problem by shaving it down slightly.

In this particular case, my money is on a various mishmash of parts not agreeing with eachother.

[VoidSuicide]

I'd say the mishmash too. Considering all 6+ mags that have been tried work about the same.

How much is slightly? I know it obviously has to be enough that it doesn't block the hopup unit.

[Bushmaster]

Not sure if this'll fix it, but it's worth a shot. When my G36 wouldn't feed because the air nozzle didn't retract all the way I just shimmed the hop-up forward a little using cardboard and it then fed flawlessly.

[VoidSuicide]

So, I just test fired it a couple times on semi. And it seems that the nozzle is stopping a bit randomly, sometimes clear of the barrel, sometimes blocking it partially or even fully. Could the problem be that something has come loose and that the nozzle not properly attached to the piston or whatever it connects to?

[Skywalker]

Yeah, it could be out of place with the tappet plate.

I know on one of my guns, the hop up unit just generally wore out after 4 years. I know it sounds like BS, but I tested and replaced every little thing until I just gave in and ordered another hop up. And it fixed it 100%. Although, my issues were more double feeding.

[VoidSuicide]

So I guess I will be opening the gearbox once I have some time to do so. I'll post an update when I do.