Catastrophic Failure of V2 Mechbox
 

Received an AEG from a client. He said it was make "grinding noises and not shooting". The gun is a cansoft MP5 with a Cyma mechbox. I guess I have finally met a "Broxa" ? This was the first time I had to tell someone that the repair bill would be more than his/her gun is worth - it is a total loss.

Anyway upon first inspection I saw his problem:

http://s650.photobucket.com/albums/u...e/DSCN8291.jpg

Yup, typical V2 break area.
Replacement shell is only $30-$40. (And I guess a gundoc fee).

Unless other parts are broken too.

I've seen worse lol
Get a G&P mechbox shell!

CM03, the infamous old gen of GB in old previous CYMAs.
Glad they corrected that...

JB weld, duck tape and for good measure some bubble gum :rolleyes:

Don't laugh at bubble gum, I used that for emergency seal one time ;)

Thats a typical V2 blowout. Nothing special.

This can happen to pretty much any gearbox, doesnt matter what brand.

Though the durability has been improved marginally by reinforced boxes, sorbo pads and not playing in the cold.

OHYA, and sorbo pads greatly reduce the chance of that happening lol

I have 3 mechboxes here now with the front ends cracked.

Yea.. well I have 5 gearboxes that are in perfect condition...

So there!

Has anyone tried an STS with a broken mechbox front end?

I am running low on those. I do have a Bravo 7mm reinforced that I am saving for something special.

I have a polymer V2 coming, just to test it out. My buddy assures me that they are better polymer than they used to make. I will do a review if it is worth anything at all when it arrives.

how does the polymer react to grease over the long term?

my next scratch build V2 is going to be the torus box pimped out with only modify parts and the ASCU. lol

I tried the torus and modify stuff build... It's ok, nothing special.

Seigtek gears, Kanzen bushings, Ars piston head, cylinder head, spring guide, Tokyo Marui Piston Body, G&P 8mm shell... and Prometheus everything else :)

Amos, in your opinion, what is the strongest Ver 2 i would be able to pick up now?

It works but not great, there is still air loss. Better to use an STS on a non broken mechbox :D

It works. Even with Airsoft Surgeon Stage 6 springs. You get massive air leaks but the gun shoots reliably enough to game.

Rofl, with the losses i'd expect with a gearbox looking like that you could advertise it as an air-cooled gearbox ;)

when i was in england i only saw 3, maybe 4 gearboxes that had cracked (all ver.2) but only one as badly as that, thankfully i've never had it happen to me..

*knocks on wood

Manufactures and gun-docs can easily remedy the situation by just de-stressing the front of the mechbox by radiusing it (before it breaks of course). Its a basic ME principle to eliminate the stress fracture points.

BTW...most mechboxes that claim to be "reinforced" are reinforced in the wrong places. Marketing BS to make you think your getting a stronger box when in fact your not.

^Ya they seem to be reinforced in the back mostly. Which is pointless cause they break on the front lol. As far as V2 goes I run a cheap mechbox so if it breaks its cheap to fix. I am running one of those black JG ver2 boxes. They are great for $60 and of they break it only cost $60 to replace.

Well it doesnt matter what you do to the mechbox if it's a marui. The only way to prevent those from breaking above 330fps is with the ARS sorbo cyl head, or adding a sorbo tablet to your current cyl head.
Beyond that, you need a better metal, G&P makes mechboxes that are tough as nails, they've got some of the best low quality metal that airsoft guns can be made out of, that's why we all LOVE their M4's lol

I'll second that. I had 2 TM mechbox shells snap off like that - one at 360 FPS, and one at a mere 340 FPS. It's quite normal as the original V2 design was intended to be fired at sub-300 fps velocities.

Reinforced mechboxes ftw. Not expensive and will save you a lot in the long run.

It seems like even G&P gearboxes are not immune to cracking either: YouTube- G&P m4 special forces problems

No V2 box is immune to cracking. I dont care what people say.
Ive seen every brand out there break in one way shape or form.

300fps and Sorbo pads make it immune lol