G&G CR16 firing issues

[HarryBaker]

Hi guys,

just wondering if anyone has any advice for one of my old guns that's stopped firing. The gun is this one: https://www.zerooneairsoft.com/product_info.php?products_id=6354 and I bought it second hand a few months ago off of a guy at my regular site. Now it has become a spare gun for friends to use when they come airsoft for the first few times until they want to commit to buying gear.

The issues started a few weeks ago whereby the trigger kept getting stuck after shooting in Semi. The trigger would Jam to the point where it was almost as if the safety was on and the trigger could not be pulled back. When putting the gun in to full auto, pulling once, and returning the Semi, the issue appeared to resolve itself for a while. Thinking it was probably something minor the gun was used again this week by another friend but some different issues appeared.

The gun then stopped firing in full auto and semi altogether. The trigger would get pulled back but nothing would happen (gears/motor). There is a distinctive click when pulling the trigger back that I can't remember whether this was there previously when I used to use it or whether this has just occurred with this issue. Anyway, after messing with the trigger for a few seconds the gun came back to life and was shooting again fine for about 15 minutes. After this, the gun is completely dead. The trigger pulls, but it is almost as if there is no power coming from the battery.

Now, I've taken out the fuse and tried to "Bypass" it to run a test shot but either I didn't do it properly or the fuse is fine and the issue lies somewhere else. After looking around online, I've ordered a trigger contact V2 and am going to open up the gearbox and replace this to see if that resolves the issue. If this doesn't work I'll also buy a fuse Sunday at the field and replace that just to rule it out.

I'm wondering if anyone else has any other ideas if these don't work? These were just to 2 easiest things that I read about that supposedly fix quite a lot of issues like this and considering the trigger had issues and is now clicking, it makes sense to me that the trigger contacts has bust.

Any suggestions are appreciated ?

Harry

 

[adox]

The first issues about not firing and then going to full auto and back to semi is a common problem. It happens when you fire too fast and the anti reversal comes in to play. (at least I am pretty sure). It has nothing to do with the other problem to which I really have no idea. Sorry

 

[HarryBaker]

The first issues about not firing and then going to full auto and back to semi is a common problem. It happens when you fire too fast and the anti reversal comes in to play. (at least I am pretty sure). It has nothing to do with the other problem to which I really have no idea. Sorry

Yeah I did have a feeling that these were unrelated to be honest

 

[RR01]

Unless the gearbox is fitted with a microswitch, it could be that the moving contact is worn and allowing the trigger to push past it so that it does not move far enough forward to connect with the fixed contacts.  Also the fixed contacts can get burnt out and not allow current to flow to the motor. In either case a strip down should show the problem.

 

[Prisce]

@Iceni is the man to speak too. 

He explains a lot better than I can.

 

[Iceni]

It sounds like the trigger dolly is worn out. There's a small step on the trigger dolly that interacts with the trigger. The step can get worn down with age, and the dolly can stop moving freely in it's rails.

It's a common enough problem with older guns. It could also be the contacts have spread out a little with age, the new unit will solve all of the issues.

If you can solder it's a £4 repair. If you can't solder or are bad at it buy a full loom for under £10.

https://www.ak2m4.co.uk/internal-parts/trigger-switches/ra-trigger-switch-v2

https://www.ak2m4.co.uk/internal-parts/trigger-switches/v2-trigger-switch-rear-wired-deans

Replace the whole unit if possible (contacts and the dolly) otherwise you might run into compatibility issues.

Whilst you have the gearbox open:

Check the airseals, and replace the O-rings on the piston. Standard is 19mm (ID) x 2.5mm

And if the gun was shooting at Low FPS do the mainspring as well. M100 is the safe bet for 330fps.

Regrease with good quality moly grease on the gears, and good quality silicone grease on the O-rings and cylinder.



 

 

[HarryBaker]

It sounds like the trigger dolly is worn out. There's a small step on the trigger dolly that interacts with the trigger. The step can get worn down with age, and the dolly can stop moving freely in it's rails.

It's a common enough problem with older guns. It could also be the contacts have spread out a little with age, the new unit will solve all of the issues.

If you can solder it's a £4 repair. If you can't solder or are bad at it buy a full loom for under £10.

https://www.ak2m4.co.uk/internal-parts/trigger-switches/ra-trigger-switch-v2

https://www.ak2m4.co.uk/internal-parts/trigger-switches/v2-trigger-switch-rear-wired-deans

Replace the whole unit if possible (contacts and the dolly) otherwise you might run into compatibility issues.

Whilst you have the gearbox open:

Check the airseals, and replace the O-rings on the piston. Standard is 19mm (ID) x 2.5mm

And if the gun was shooting at Low FPS do the mainspring as well. M100 is the safe bet for 330fps.

Regrease with good quality moly grease on the gears, and good quality silicone grease on the O-rings and cylinder.



 

Thanks so much for the info! 

I've ordered the part without the wires which sucks as I don't have a soldering iron. Will reorder with the wires and then see if that replacement helps ? Will also do all else that is suggested especially the spring and grease

 

[Iceni]

Just make sure you get the correct wiring loom for your gun. There are a few variants.

I linked to a rear wired (battery in the stock) using deans connections.

Chances are your current loom and batteries use small Tamiya connectors. I personally prefer deans connections because they have a better current carrying capacity most would class deans as an essential upgrade as well.

If you go with the deans loom just be aware you will need deans batteries as well. You can solder the connection onto any battery, but you can also buy them pre-done. Component shop offers deans as an option. 

If you want to stick to small Tamiya then make sure you get the right loom, Most of the online shops will sell some complete loom variants.

https://www.bullseyecountrysport.co.uk/element-silver-wire-set-for-version-2-gearbox-rear-wired-version-tamiya-11176-p.asp

For the O-ring go to a bearing supplier. You want 19mm internal diameter and 2.5mm cross-section, in nitrile (buna-n). 10 are about £4 and 50 £6.

https://simplybearings.co.uk/shop/Seals-O-Ring-Seals-NITRILE-O-Rings/c19_4501_4705/index.html


 

For the grease, anything you have should be fine. If you want to get gearbox specific grease then this is what I use, It's not fancy but it works.

https://www.ebay.co.uk/itm/FOOD-SAFE-SILICONE-GREASE-WITH-TEFLON-50g-TIN-MFP2HT-PLASTIC-SAFE-LOW-FRICTION/392141463862?hash=item5b4d73e136:g:4sYAAOxyuCJRbx-p

https://www.ebay.co.uk/itm/Molly-MOS1-Grease-for-Airgun-Servicing-50-GRAM-TIN/392238283947?epid=595843240&hash=item5b53393cab:gckAAOSwwSJcJmb5

Others will say you want fancy grease, I'm not one of those people.


You may want a set of shims if you are feeling adventurous and you will need to examine the internal parts for wear. Bearings and air seal nozzles are common failures, and opening a gearbox can often show up faults you didn't expect.

Watch a few video's on shimming, Watch a few video's on compression testing.

Items like grease tend to last a very long time, and o--rings are universal across most gearbox designs. So If you plan on having a decent collection in the future it's money well spent. 

 

 

[HarryBaker]

Good news is that the trigger contact was causing the electrical issue so replacing just the dolly appeared to fix that.

The issue I have now is that the gearbox jammed presumably because of the Reverse switch thingy... I'm also worried about the air seal in the cylinder head as it seems non existent

Either way, after 3 1/2 painful hours, I now understand how the gearbox works so I guess that's a bonus

Just need to do some research on how to ensure the air seal is tight and give it another crack. I also lost a shim in the process so need some of those ?

Thanks for the advice as the electrical issue is resolved