3DG G17 V2 Dive in and Mods

Apologies for starting another thread but this will I expect be ongoing and somewhat exhaustive.

Barrel I/D: 7.3mm
Barrel length: 8.1cm (6.8mm + 1.3mm in t-piece)
Spring: 1.15mm X 11mm x 77mm
Battery 11.4v 420mAh 60C

Please bear in mind that opinions can change with new learnings.
Some niggles could turn into non-issues or new issues may be revealed.

Yes, when you find a gel that suits along with a better understanding of how to get the most out of it.
I ended up using Hornets and WI Reds but I’m sure many will work and work well.
Have AKAs and Ultras en route.

See ‘1’

3 PROs
Looks good. 1:1 scale.
Feels solid with good weight and balance and solid trigger pull (feels like 3-4lbs).
Accepts most aftermarket add-ons.
Smooth action.
Slide, buttons, catches all work properly.


Unlike other blasters, the barrel screws over the t-piece which forms part of the barrel, ~15%.
So it is surprising to find the 2-part t-piece/receiver poorly finished both inside and outside. There are moulding ridges and overhangs at the end where it joins the barrel and ridges inside that should have been polished out.
One wonders how many gels get damaged here.
A barrel that screwed INTO the t-piece would have been better.

This should just be a thin washer located inside or outside. As it is, it bulges into the barrel when tightened.
Removing the o-ring entirely creates a new problem as there is a (1mm) clearance built in the barrel threading to allow for it.
Remove the o-ring and screw the barrel in as far as it will go and that gap remains. The only way to get rid of it would be to shorten that end of the barrel (more later).
Again, this is less likely to be an issue if the barrel screwed into the t-piece.

Barrel threaded area: 11.6mm
T-piece exposed length: 10.6mm

Not sure if a hinged door is a big plus apart from not losing it (I reckon the hinge should be on the bottom).
A loader will be handy but every owner will have his/her own “best way”.

When the slide locks open, there will still be 9/10 gels in the feed tube and 1 at the top of the mag. This in not unusual in pistol GBBs except most have mags that hold 30-40.
These have to be removed/tapped out before storage as shooting upside down does not appear to work well here.
Gas and CO2 blasters do not have piston assemblies and the gels feed almost directly up into the t-piece. This also allows for longer barrels within the same size shell.

This does require difficult cap removal. It is easy enough to bend (at every recharge), shorten cables or even shape a slot for it outside.
see mod pic

at top of mag may need a softer spring. It is there to keep gels in, not to test their hardness but it’s a balance between this and the spring trying to push the gels up and out.
Either way, some finishing/sanding/contouring could help. This is possibly where initial gel damage can occur esp. when mag is inserted and mag spring released.

This spring is not that relevant as the retainer is pushed aside by feed tube anyway when the mag is inserted.

Muzzle end of barrel could have been threaded and come with a thread protector. Yeah right.
There is room for it.

Long Feed Tube is non-tweakable. Sorry. :woozy_face:

After a bit of finishing and gel testing, it feeds and shoots consistently although fps still varies but that could settle in time as others have noted. Only 10 mags so far.

Do not see need to alter springs or cut/grind anything else, yet.

Design 4/5
Materials 4/5
Finish 2/5
Overall Build 3/5
Out of Box Performance 2/5
Bang for Buck 2/5

Seal and spring.
Autofire? :woozy_face:

The 370 motor needs juice and the 60c supplied is necessary.


yikes…that’s put me off…

although i am really wanting gbb pistol

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Keen to see how you go with seal and spring. It definitely has a weaker spring in it than we were promised with the V1. Though they may have lowered the spring to avoid stripping gears.

I have gotten mine shooting every single shot with both soft gels and hard gels and am just seeking performance now.

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A strip down will tell me if gears are unique. I know of 3 distinct types currently available.
As for springs, I happen to have some 1.4 X 11s on the way. :sunglasses:
That being said, I’ve seen comments regarding the spring but try squeezing it and it becomes apparent that because of the small diameter, even at 1.15mm, the coils are tighter and it feels more like a 14mm 1.5.
Not sure I’m game to even add spacers, yet. :grin:

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Hey mate, I have mine pulled apart as obviously doesn’t work properly like some others. Apart from the things you have stated which I think I had already ironed out over the last few days, seems now that the sliding plate …that I think maybe what is a tappet plate in other blasters … gets sticky and seemingly stuck.and stops shooting With the feeder tube removed I could pump it full of bells and then would have to poke them out! Sanding and a little buffing and deburring edges then had the gells rolling out freely even if poked in there till some smashed. Do you know of a good product that can lubricate plastic in these things apart from silicone oil / grease and the typical sprays? also do they put any lube on the piston, piston head, the nozzle and or inside the cylinder?

I use Inox.
Esp. on fast moving surfaces.
It’s light and doesn’t dry out or collect gunk like the more viscous lubes and has properties that suit this hobby and the materials used.

Agree with the sanding and trimming. It should not have been necessary.

Haven’t looked inside the gearbox or cylinder yet but there was a huge lump of some bluish-white lube coming out the back under the gearbox.
With the ‘attention’ noted elsewhere, I’m guessing they would have slapped some thick lube inside the gearbox and cylinder.

Gel retainer contoured and edges rounded.

MOSFET Resoldered.
It’s a peace of mind thing as it works as is but I’ve seen much better and sloppy workmanship bothers me.
As for the 2 hard lumps of glue, no idea what they’re for as they fell out when opened.
I also had to cut out a section of yellow lead as it was split and could have grounded on side of motor.


Innox rocks but I’d be using Super lube on that

Inox mx6 just as good as super lube.

I use superlube red, usually on metal gears and bearings.

Barrel connection 1mm gap.
Measurement shows a set gap between the internal threaded section of the barrel (11.6mm) and the length of the gearbox/t-piece it screws onto (10.6mm).

This means there is a designed limit to how much any o-ring can be compressed. So while owners can turn the barrel to adjust how much the o-ring is squished and bulges into the bore, it can not be squeezed thinner than 1mm.

This could be handy but also creates several issues.

1 Not using an o-ring at all will always leave that 1mm gap.

2 With an o-ring, unless the barrel is turned until it bottoms out, it can loosen and that bulge can vary.

3 Being part of the gearbox shell and split down the middle, there is nothing to maintain a good seal along the threaded section. The o-ring only seals where barrel meets t-piece.

4 How does one align a hop up on the barrel with this kind of setup?

Possible fixes.
1 Use a flat washer at the bottom of the threaded section of the t-piece. That way it doesn’t matter if air leaks out the split along the thread.

2 Discard the o-ring and shorten the barrel by >1mm. This ensures a tight seal irrespective of the split in the threaded section and a consistent stopping point when screwing on the barrel. Hello hop up. :slightly_smiling_face:

3 Use PTFE/plumbing tape on the thread in addition to some/all of the above.


170+ average.
Tweaked mag retainer and spring and with barrel mods, feeding issues gone but still get a burst gel on average 1 in 10.
It now does 170+ with the occasional 190+ which is just matching other pistol blasters.
If not the mag or the speed, the suspect is now the feed tube.

Need to try with AKAs or Ultras next.

Sorry, I have added a spacer to the spring retainer.


Hi any photos of the spring packing

No. But I will take some.
It’s all back together now so I’ll open it up again and post it.
Frankly, I wasn’t sure if it’d crap itself but a dozen mags later and no probs, yet.
Working on a hop up idea now that the barrel stays where it’s put.

Cool , thanks , my 3DG plays up occasionally, looking forward to seeing the spring spacer , ? What size was the spacer , rubber or washer . Cheers Fred

5mm. Was a risk.
As always, I ground the ends of the spring to remove all sharp bits beforehand.

Sorry, it was just over 8mm.

Cool I’ll give it a go .

Redid leads to XT connector, shortening about 2cm on mag side and shortening solder lugs on battery side.

Much easier to replace cap.

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When a mag is fully inserted, the feed tube pushes back the retainer in the mag and the mag spring is released and shoves gels into the feed tube as far as possible.

This being the case, the strength of the spring behind the retainer becomes irrelevant.

Anyway, this release of the gels mean that no precharge is needed. It is why your first shot will usually send a gel flying.

This is however a sudden and violent action and can be when gels get damaged. If so, it is a good reason to weaken the mag spring and smoothening any protrusions along the way (and using harder gels). :slightly_smiling_face:

Anyway, if this is happening with your pistol, you should be able to insert the mag and straightaway, release it and top it up knowing the feed tube is now full.
This may be preferable to shooting the 10/11 gels before reloading, if it works.

5 coils off mag spring and stretched retainer spring works with hard gels. It still pushes out 5/6 gels.
What a hassle.
Basically, the retainer will only hold the gels back (with the spring released) if it had more travel and blocks off half the tube.
Otherwise it doesn’t retain much. What a bother.
Back to the drawing board. :frowning: