JG V.3 Precision Full Metal Gearbox (reshimming)
 

Im new to airsoft with aeg's, (only one i ever use is a cheap 29$ aep), and I want to upgrade my gearbox(i got the jg m16a4 RIS DMR Advanced 2011 edition). The problem is, I dont know what is already included in a JG V.3 Precision Full Metal Gearbox. My questions are:


Exactly what parts of the gearbox are metal (brushings)?
Compared to other gearboxes, what is the quality of this one?
Does it come pre-shimmed?
What kind of shims should I get?
What kinds of tools/Lubricant should I get?
Will this make the gearbox quieter?
Other things I can do to quiet the gearbox?

Having a well shimmed and lubricated gearbox will make it quiter. To find out about making it quieter, do some research, there are tons of threads on it.
Just basic tools: screwdrivers, allen keys, magnitizer etc... I use ICS Gear Grease, but I don't think it matters a whole lot.
No, they are not pre- shimmed.
Kind of shims don't really matter.
It's decent quality compared to others.
Can't tell you exactly what's metal in it. Could you post a link of the gun?

It has a version 2 gearbox all AR's do. It is JG's 3rd generation of their version 2 gearbox though.

mechbox.com is a great source for when you need to upgrade but use the gun first and learn what and when to upgrade before jumping in right away.

Oh yeah Tex is right, your gun mechbox is a V2, didn't notice the part that you had an M4 haha...

The gun
 

here is the gun,
http://www.airrattle.com/The_JG_DMR_...me_p/f6620.htm


fired about 50 rounds from it today, and all of a sudden, when i pulled the trigger, nothing happened, no noise, no response, nothing. I may have the trigger pin problem. Ill check and get back to you guys.

check the fuse.

After being in my Echo 1 gearbox one time, I tightened the screw that goes through the trigger too much and had the same problem, so that could definitely be it.

What Tex said.

And if the fuse looks good, then check the connectors on the motor - one might have popped off.

Two more questions.
 

Yeah, it turns out that it was the motor height adjustment screw that was out of whack. I just tightened it a bit, and it started working. Also, what is a magnetizer. Well shooting with .25 bbs, it is really precise at 50ft. i just just need to sight in my Leapers sight, and adjust the hop up.
two more questions:

How do I know when my hop up is adjusted correctly?

Are scopes more acurate if you attachthem via converter to the carrying handle? or directly to the RIS rail on the top of the rifle?

Metal Brushings?
 

Also, no one ever told me if the gearbox came with metal brushings?

A magnetizer is a little tool that you can stick screws threw, and it magnitizes them. It just makes it easier to put screws into tough places. They aren't a necessity.
Do you mean metal bushings? I don't have the gun so I can't say for sure but I think they do, cause JG's usually do now.