G&G UMG Magazine Double Feed

[nb]

So here's the deal.
I'm having double feed issues with my UMP.
After searching some on google, as well as here I've found it is/was a common problem to see G&G 70 rounders double feeding with the gun.

I'm almost certain it is indeed the 70 round standard magazines, since the one highcap I own does not double feed.
The four standards do.
I've heard a solution to this problem is to crack open the magazines and chop a few coils off of the spring so there is less tension.
Can anyone speak to this?
I've gone in blind on things like this before and they usually do not end well, so any advice would be much appreciated (i.e. how many coils to chop off, a different fix, etc.)

Also, it might be worth noting that the four standards used to feed fine. Perhaps they only double feed because I haven't used the gun in awhile?

Boy, it's been awhile since I started a thread.

[MillerSA15]

Try filling one up all the way and just letting it sit. That might take enough tension off the spring to make it work. I would let it sit for 24 hours or so (just with 1 at first). If that works, repeat with the rest.

[nb]

Well the thing is this problem actually started happening near the end of summer.
I figured I would try that, so I filled the magazines and let them sit until yesterday.
So it's been almost six months storing the magazines with a full load and no significant decrease in spring tension.

[MillerSA15]

Well the thing is this problem actually started happening near the end of summer.
I figured I would try that, so I filled the magazines and let them sit until yesterday.
So it's been almost six months storing the magazines with a full load and no significant decrease in spring tension.

Wow, that is crazy.

[phiz]

You might replace your hop up bucking and make sure the hop up is on. Double feed probably means the spring is pushing the bb past the hop up bucking and into the hop up nub. Thats my current theory.

[Bulldog]

Check the hop out,

Do you know what version you UMG is?
When they first came out some had a flawed tappet plate which caused this double feed. I know this as I had to deal with it. Once they fixed it I just bought the version tappet plate and hop-unit. Worked like a champ until I got rid of it.

Good luck

[nb]

I've heard of the tappet plate issue as well.
I'm not sure what version the gun is. Is there any way to tell? I don't have the original box--bought it used off of Heretic way back in the day.

I'll test out messing with the hop-up and see if I get some results.
From what I've seen the one high-cap I have doesn't double feed, but I haven't tested it all the extensively.

So no one has had any experience with cutting coils off the spring in their mags?
I'd hate to have to go in just chopping away without any knowledge of how much to cut.