M16VN - Inconsistent FPS, Blank fire on F/A

[StRiCkEn]

I've been having a few issues with my M16VN. It's a WGC Shop custom. Their website is www.wgcshop.com

I can't provide a direct link to the AEG but here is a copy/paste from the page on the web site.

All WGC Custom AEG base on:
- G&P 7mm Reinforced Gearbox
- Reinforced Polycarbonate Piston
- Bearing Spring Guide

Fitted with G&P High Quality M16VN Metal Body
M16VN Metal Front Set with One Piece Barrel to enjoy the Reality and Heavy Weight!
G&P Solid Stock
G&P Enhanced Pistol Grip with Heat Sink to reduce overheat problem.
G&P M16 110Rds Magazine ensure feeding BB with smooth & fast

Specifications:
Built Material - Metal & ABS
Gear Box - Version 2
Motor - G&P M120 High Speed Motor
Magazine - 110 Rounds ( 6mm )
Length - 992mm
Weight - 2660g
Muzzle Velocity - 330-360FPS with 0.2g BB
Battery - 8.4V Large Type ( 2000mah or above / Not Included )
Package includes ( AEG, Magazine, Manual )

It's an amazing AEG when it is performing properly, but some inconsistencies are frustrating the crap out of me.

I attended a game last month and at the pre-game chrony it was firing at 116 fps. I was pretty pissed. So I fired off 15-30 rounds into the brush while someone else chronied. It started working properly long enough to chrony for a consistent 369 fps.

As well, I am having issues on F/A, inconsistent blank shots fired during trigger pull. I see there is a post dealing with a TM-based AK-type AEG, which was solved by installing a different nozzle.

So from what I can deduce, my problems are:

1) Inconsistent FPS - No idea what is causing it. My first guess would be air seal problems. May be fixable with a new nozzle..? Any other opinions are appreciated.

2) Blank shots on F/A - From what I've read, I'm also assuming this is an issue with the nozzle. Any other possibilities?

Any help is greatly appreciated!

[mcguyver]

If it's a complete G&P mechbox, what does the cylinder look like? If it's the silver-coloured one with ridges, then you will have a problem here. Those cylinders have a matte internal finish and sometimes poor lubrication. This can be a problem with shot consistnacy as well as longevity of the piston head o-ring. If it has this cylinder, it's likely a 2005-version mechbox and may also have the steel nozzle with the airseal o-ring. Replace this nozzle with another one 9different manufacturer) or remove the internal o-ring. You'll lose a few FPS, but it greatly increases the lifespan of the tappet plate as the cylinder head outlet also has this matte finish and makes for alot of friction against that nozzle.

The problem may also be in your hop-up as well. If this gun has sat for a long period of time, the hop-up may be dry and a little over engaged. Turn it all the way off, put some silicone oil in there (a drop or 2) and fire a few hundred rounds through it. Then re-adjust the hop-up and see where you are at.

[Renegade)]

Def sounds like an airleak problem, nozzel, cylinder, piston head, ect.. Check them for lube issues and airseal (ways to troubleshoot this can be found in the doctors corner already)

[StRiCkEn]

Alright thanks a bunch. Yes, it does have a steel nozzle. I'll most likely replace it as you have advised. Nozzles aren't too expensive from what I gather. Would this one be a good choice?

http://www.airsoftparts.ca/store2/in...roducts_id=552

From what I have heard, Deep Fire seems to be a good choice to go with.

Now, as for the cylinder - It's appears to be brass rather than silver, and I can't recall seeing any ridges anywhere.

I will definitely do the whole silicone shot into the hop unit, however I can't see it being an issue. I've had the AEG for about a month only. However I suppose it may have been sitting in a box for a long while before I got it.

[Renegade)]

Lube the hopup, if you are familiar with taking the mechbox appart, lube the inside of the cylinder, piston head, nozzel, shaft nozzel slides on, ect and then test it for seal. That should help your air problem.

[mcguyver]

It sounds like you have a 2006 version mechbox. The cylinder and nozzle issues were solved in this one that I mentioned for the 2005 version.

I would concentrate on the hop-up right now before you go tearing the gun down. Best to eliminate easy fixes first before you tear that puppy down.

[StRiCkEn]

Alright thanks a whole bunch. I've gotta go to sleep now, gotta get up early for work tomorrow, so I won't be replying again tonight.

What should I use for lubing? I'm assuming standard weight silicone oil for the hop-up, and some sort of grease for the internals. What would you recommend?

[mcguyver]

G&P makes a lube kit for their mechboxes with cylinder grease (a heavy-weight silicone oil), bearing oil and gear grease. It can be had for about $10 U.S. from most Asian retailers.

[Styrak]

Do you know how to take that gun apart? If not, I can help you out Stricken.

[StRiCkEn]

As of now I can only field strip it. I have neither removed the mechbox from the lower reciever nor taken it apart. I have a general idea, though, from watching the V2 gearbox takedown/reassembly at mechbox.com. However, if I could get some hands on help from you, Styrak, that would be great as well.

I'll maybe wait until I get home and spray the hopup rubber with silicone, and open the mechbox before I order any parts online.