VFC Quake m4 Riddle

[Trev140_0]

So here is a good one. I figured the problem out already but we so bizarre I decided to post this.


See who can guess the problem.

Gun. Stock m4 VFC quake.

Only thing changed is the stock piston. Swapped with a 4 tooth metal. Same tooth count as stock.

Here it the problem. Shoots fine then gets "stuck" every once in a while. Always stuck at the furthest point back. Piston all the way to the end. Basically like where a mosfet should ensure the piston doesn't stop.

So then it's basically jammed. Can't cycle it. Got to crack it open and Re set it.

So here are the things that you need to know.
Battery and motor are fine. So is wiring. And trigger contacts.

Figured would cut that out so you try and get to the problem .

Again was ridiculous but something that should be passed on....

Go.

[Trev140_0]

Ps I go lucky finding the problem cause this one was messed up.

[Ron-E]

crooked piston stuck on the gearbox piston rails?

[lurkingknight]

I've had 1 or 2 guns cross my bench with this.. it was trigger switch related. The shuttle would not reset properly and float on top of the gun trigger.

SHS trigger contacts would do this on a vfc 416 I was working on. On closer inspection the cutout for the cutoff lever was different shape on the shs shuttle. Put the vfc shuttle back in and it worked.

The other gun was an SRC 416 with a src gearbox with g&p trigger switch and trigger. Once I swapped back to the src bits everything worked fine.

[_Whiskey_]

What spring are you using? Strength and brand? I had a modify m90 that jammed my gun up like yours switched out the spring for a element and it worked fine since.

[HKGhost]

VFC gearbox shells are more thinner than others. So you'll need to use the thinnest pistons like SHS, TM or Magic Box to work without modding.

[Trev140_0]

Ha!
No
No
No
And....no.

[Trev140_0]

But Rene is in the neighbourhood...

[chaz]

You used the wrong "lube"?

[Trev140_0]

Originally Posted by chaz

You used the wrong "lube"?

jackass.....


Always about the lube with you....

[Rossco66]

Your piston head caught poison ivy?

[Trev140_0]

Alright....so here it is.....

When looking at the internals a second time, I checked out the spring, piston etc again.

Then I decided to look at the spring guide to see if there was some kind of scraping or something.

So get this, picked up the spring guide and holy shit. The spring guide came un threaded. ALOT!

So the spring guides on the stock VFC have a TWO piece spring guide. One part is a threaded rod that screws into the backing.

This threaded rod actually unscrewed about 8 to 10 turns easy. This essentially lengthened the spring guide. This would then act as some weird HARD STOP and hit the BACK of the piston-basically stopping the piston from being able to fully retract.

Absolute most ridiculous thing ever seen.

So threaded the spring guide back together (in a VICE) and problem solved.

[chaz]

You might want to throw some blue loctite on that sailor.

[lurkingknight]

ah yes, I have a vfc gearbox in my parts bin with that exact issue. I had forgotten about it.

VFC owners, loctite that shit.

[GBBR]

your gearbox is jamming on the spring, and spring guide, the spring will try and thread itself to the spring guide and when your piston gets pulled back it gets jammed. i can take pictures for you tmrw if you like