View Full Version : building a mechbox from scratch

10-11-2004, 01:24 PM

i want my next aeg (a sniper project) to shoot around 500fps. i have been unable to find any of the pre-built mechboxes (for m4/m16) in stock for this fps, so i've resigned myself to building one from scratch (gulp!)

if i get a: reinforced ver 2 mechbox, an m150 professional ftk, trigger set, grease/lube, will i have everything i need to build a complete mechbox? do i need to buy a spring set(the little tiny springs, not the one big spring)? do i need extra shims or anything like that? the devil is in the details. what am i missing?


10-11-2004, 05:47 PM
www.dentrinty.com search for Fastec or Progear. They have what you need.

10-11-2004, 07:28 PM

thank you for the reply. i've already looked at dentrinity, as well as uncompany and redwolf, and unfortunately the pre-built mechboxes that i want (m140 for the m4 or m16) are not in stock, and they tell me they won't be re-stocking these anytime soon. hmm, what to do.

thanks anyway.

10-11-2004, 08:10 PM
-Pro FTK for M16A2 (includes gear set, cylinder/cylinder head, nozzle, piston, piston head, spring, spring guide, tappet plate, trigger switch, bushings, anti-reversal latch, gear shims, selector plate)
-mechbox spring set
-reinforced mechbox shell

The trigger should come from the gun you are modifying.

10-11-2004, 08:35 PM
Or go look at the new GRS mechboxes that WGC just started to carry.

10-11-2004, 08:47 PM
440fps is the strongest spring they offer, not that you couldn't swap it out to gain more velocity. No idea on what parts they use in there either, so not sure I would front the money on it without knowing what is in it.

10-11-2004, 09:35 PM
thanks to all for the replies.

obsidian--yeah, i found those grs mechboxes, too. and, like austinwolv says, i was a little leery of buying one without knowing what was in them. so i sent them an email, now just waiting to hear from wgc regarding the contents of those gearboxes. cause that would seem to be the easiest way to go--get the mechbox set and just upgrade the spring (assuming the rest of the mechbox guts will take that heavy of a spring).

when i hear back from wgc i'll be sure to post their reply. thanks again for everyone's help.

10-12-2004, 08:51 AM
ha good luck. I have issues getting them to mail me back quotes and stuff and we have a dealership with them. I wouldnt wait to tell you the truth. I would either take the leap of faith and get one or go with one of the other plans :)

10-12-2004, 09:20 AM
really i get a 24hr or less response time/feedback.

10-12-2004, 10:13 AM
lol obsidian, they must not like you or something. i sent them an email last night and got back a reply this morning. here is the vague, fairly uninformative response they sent me:

Hello, GRS Full Gearbox Set mainly design for G&P M16/M4 metal
receiver, but it also can work on Marui AEG, it includes those
internal parts, reinforced gear, gearbox, 7mm bearing bushing...

so i've sent them another email asking them to be a little more specific, and try to provide a parts/manufacture list of the mechbox internals. we'll see what kind of response i get this time.

thanks to all.

10-12-2004, 01:37 PM
Pre-built is the way to go if you aren't upgrading a stock mechbox as there are a couple parts, like the cutoff lever, that aren't included in any kits or as an aftermarket part.

Good luck.

10-12-2004, 02:04 PM
Damn, good catch, Falcon. Forgot about the cutoff lever. There's always one little part to throw you off.

However, both Guarder and Systema market them for Ver2 mechboxes.

Emailing retailers could likely net a person a stock TM cutoff lever as well.

If anything, a lot of those little parts can be found cheap in the classifieds section at ASP when people sell off their stock mechboxes.

10-14-2004, 07:41 PM
well here's a little follow-up on the grs mechboxes at wgc. i had emailed them asking the contents of those mechboxes, and got back these responses (in two separate emails):

"Hello, GRS Full Gearbox Set mainly design for G&P M16/M4 metal
receiver, but it also can work on Marui AEG, it includes those
internal parts, reinforced gear, gearbox, 7mm bearing bushing...


"Totally made by G&P, includes flat gear set, poly carbonate piston,
metal spring guide.

Best Regards
Jo To
WGC ( Hong Kong )"

"totally made by g&p?" this doesn't quite make sense to me, as i wasn't aware that g&p made things like springs and gears...also, for the advertised fps (~420 or so) wouldn't torque up gears be more appropriate rather than flat gears? i HAD been leaning towards getting one of these mechboxes, but now i'm not so sure.....maybe the good folks at wgc just don't have any idea what's in those shells. should i trust whoever made these sets that they knew what they were doing? anyone have any advice or comments?

thanks to falcon for your help, too.

10-14-2004, 08:02 PM
Read this link about gears: http://austinairsoft.com/modules.php?name=FAQ&myfaq=yes&id_cat=8#35

Flat gears CAN be torque-up gears....or they can be standard torque gears. The cut of the teeth does not determine the gear ratio (torque value).

As for the parts, it seems more and more companies are coming out with product. That is a good thing since competition will cause quality to increase. However, if I recall correctly, the G&P pistons are sold under the "TGS" brand name and have been on the market for a while.

10-14-2004, 08:28 PM
thanks, a-wolv!