Shop upgraded my G&G M4 and messed it up

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AndyKnoxville

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Hi, hoping for some advice before I take my G&G M4 back to the Airsoft ship that upgraded it for me.

I took it in as it was only shooting at 230fps with 0.25g bbs. I had a good chat with one of the techs about upgrades and agreed upon a list of parts I wanted upgraded.

4 weeks later I get a call saying it's all done and shooting at 349fps on 0.2's

I picked it up and paid the £130 for the parts and labour. I never actually got to fire it at the site as I turned my left ankle literally 2 minutes into the first game.

One of my boys fired it at the range whilst I waited for my other half to pick me up and commented that it's firing every other shot (mis-shooting).

This morning I tried it out in the garden and the first few shots barely came out of the gun. Then it shot s few bbs, then when putting it on full auto a few came out and then about 5 came out (like shotgun pellets) all at once! 

I tried another mag (I use G&G usually) and it did the same thing. I barely got through the mag when it made a horrendous, high pitched squeal and I thought it was best to stop!

I've posted a picture of the upgraded parts they used.

The guns was a stock G&G warthog.

I know people will say "take it back" but I just wanted to get some opinions on the parts used, etc.

This has soured the experience for me and I don't want to end up with a money pit of a gun...

Thanks in advanceView attachment 76294

 
apart from the hop chamber doesn't seem like the worst combo. although even with good parts things can still get messed up in the assembly.

however it might not be the assembly, misfeeding can equally be caused by mags/ammo (bad ammo can jam up and the mag spring might not be strong enough to overcome it, for midcaps at least)

the other possibility is the hop setting, you can get some weird things with the hop either fully on or fully off, so you generally want to be testing with the hop set (turn it off then on a little if it's not already dialled in for the ammo)

 
Adolf Hamster said:
apart from the hop chamber doesn't seem like the worst combo. although even with good parts things can still get messed up in the assembly.

however it might not be the assembly, misfeeding can equally be caused by mags/ammo (bad ammo can jam up and the mag spring might not be strong enough to overcome it, for midcaps at least)

the other possibility is the hop setting, you can get some weird things with the hop either fully on or fully off, so you generally want to be testing with the hop set (turn it off then on a little if it's not already dialled in for the ammo)
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Thanks for the advice, I've been using devil blaster 0.25's with g&g mags.

Interestingly one of my mags looks like it's malfunctioned as the BBS look to be stuck inside (not feeding to the top). But even using another mag it's still not right as fires a few rounds and then makes a loud screeching noise.

I'll pop it back to the shop anyway and might ask that they put the original hop up chamber back in as I think my original is probably better than the nuptol one they replaced it with.

 
Agreed, Nuprol to me just means the cheapest, nastiest part they could find, at a mark-up.  It's either the scruffy looking pot-metal dial unit (which I wouldn't consider an upgrade), or the £17 plastic rotary unit that's a knock-off of the £9 ZCI unit.

In either case, it's clearly misfeeding and double-feeding, the screeching noise is a bad sign (don't use it!) and the damage may already be done in terms of a stripped piston or gears, or mullered tappet plate.

I'm really sorry, it gives me no pleasure to say this, but I fully expect the "professional" who has broken your gun to shrug it off as "Owner abuse mate, that's clearly had market stall BBs through it."

I very much hope to be wrong about that, but I'd go in prepared to be calm but firm and patient.  Bring along the BBs, mags and battery that you've been using and make it clear that what you paid for labour on top of those parts[*]was supposed to buy the expertise to avoid exactly this situation.  Oh, and I'd get a record of it in writing as soon as possible in case it ends up in a spat.

This is why I break my own toys rather than paying anyone else to do it. :(  

[*]£45.50 for equal-or-better equivalents from AK2M4

 
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Rogerborg said:
Agreed, Nuprol to me just means the cheapest, nastiest part they could find, at a mark-up.  It's either the scruffy looking pot-metal dial unit (which I wouldn't consider an upgrade), or the £17 plastic unit that a knock-off of the £9 ZCI unit.

In either case, it's clearly misfeeding and double-feeding, the screeching noise is a bad sign (don't use it!) and the damage may already be done in terms of a stripped piston or gears, or mullered tappet plate.

I'm really sorry, it gives me no pleasure to say this, but I fully expect the "professional" who has broken your gun to shrug it off as "Owner abuse mate, that's clearly had market stall BBs through it."

I very much hope to be wrong about that, but I'd go in prepared to be calm but firm and patient.  Bring along the BBs, mags and battery that you've been using and make it clear that what you paid for labour on top of those parts[*]was supposed to buy the expertise to avoid exactly this situation.  Oh, and I'd get a record of it in writing as soon as possible in case it ends up in a spat.

This is why I break my own toys rather than paying anyone else to do it. :(  

[*]£45.50 for equal-or-better equivalents from AK2M4
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Thank you so much for the above advice. I'm going back today, so will take heed of your suggestions.

When I took it in originally I discussed what they were going to be doing. They said that they would "upgrade" the hop-up unit if needed. They talked about a promy, rotary hop-up or similar. I didn't imagine for one minute I would be downgraded...

 
If it's the rotary Nuprol it's likely better than the stock dial unit (but the ZCI is much cheaper).  I wouldn't consider any dial unit to be an upgrade. It's not the plastic-vs-metal body that's the issue, it's the free play between the multiple gears on any dial unit.

It's the nature of these toys that things go wrong, and we're talking fractions of a mm of clearance between perfect feeding and airseal, versus jamming in one direction or air leak in the other.  I don't particularly blame the tech for getting it wrong, it's just that you paid them to get it right.  If they had any concerns, they could have put the stock parts back in.  I'm just thinking: What Would Luke At Negative Do?

 
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My wife just called me as she took the gun back (I'm currently immobile with my badly sprained ankle). They acknowledged there is an issue and are going to fix it. They said the reason they changed the original hop-up is because when they tested it was jamming. They offered to put it back in for me... So I can have a none working gun with other upgraded bits?

I said to my wife to tell them the reason I took it too them was because I am paying for their knowledge and experience. I've worked with cars all my life and can tell you a decent part.

I asked that they use either a Lorex or Prometheous hop-up and apparently the technician looked at my wife like she was from another planet?

They've now said they'll call me too discuss the options?

I'm so frustrated right now as all I wanted was a working gun. I have no knowledge of parts or what works best which is why I paid someone to do it on my behalf.

I've told her to go back in and too get the old parts put back in and I'll take it elsewhere.

 
Screeching noise in full auto is PME caused by the jammed bbs.

BBs essentially plug the barrel, air has nowhere to go and pushes back on the piston, which in turn can't complete its travel. Sector picks it up at s random place (teeth won't mesh together) so you get the screeching.

It will work in semi because there is enough time between shots to let the air slowly slip past the BB/rubber feed lips/piston head o-ring and let the piston complete its cycle.

I say it's the combination of hop rubber and hop unit. What happens is that the feed lips get crushed between the barrel and hop unit body, making them ever so slightly too tight. At least that's what happened with my old Ares HB when I put a maple leaf rubber in it (the unit didn't like it at all).

 
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