400+ FPS JG ver. 2 Mechbox Survivability?
 

A lot of JGs are coming out of the factory shooting 400+ FPS stock . It's commonly spoken of that v2 mechbox failure is only inevitable over time when shooting that hot after some time unless you have a reinforced mechbox or perhaps sorbo pads.

Anybody have experiences with the 2008 and newer JG guns having mechbox cracking on you? I just bought an Mp5 that is shooting 425 FPS out of the box and it's making me paranoid everytime I put the thing on full auto. I usually put it away after a few games and switch to my heavily upgraded G36 with a v3 I don't worry about so much.

I know some of their more updated lines like the 416 have bearing spring guides, etc. but I haven't heard anything about their mechboxes being reinforced to take the punishment they equip them with at stock nowadays.

Well if you maintain it properly without shooting full auto, than it will last.
Sorbo pads will work and will help you alot. Get a mosfet, and also what battery are you running it with?
If it's making you paranoid, downgrade and buy a lower power spring.

I had one crack running the stock spring and a Lipo after about 1000-1500 rounds. I was pretty hard on it in full auto and it dry fired more than I'd like due to problems it had feeding. Good mechbox but I would replace the cylinder head and piston head with sorbo and the piston to something without metal teeth.

Best to have a piston with less than half metal teeth. Better to ruin your piston than buying a new set of gears.

Neither of those will affect whether your mechbox will break. How much you shoot will.

Well, technically speaking, the faster the gun is turning over the quicker parts will fail. Also, the same gun firing at 1600rpm is more likely to fail than firing at 800 rpm, within the same number of shots fired due to the speed the mechbox is moving. If the gun fails, it might not just lock, but strip a gear or piston.

I'm running a 7.4v lipo (wouldn't put an 11.1v in there) but I purposely bought this gun for my backup and "gun that I do not under any circumstances try to open or touch" since I know that will only cause me grief and more money everytime I start to go modding or upgrading on a stock gun. I am running low caps and I fire very sparingly as my natural gameplay style so I hope it will last for awhile.

Yes but he was asking about mechbox cracking, not gears or pistons.

Shouldn't you be downgrading this AEG so it's safe to use on the field anyway? Isn't this entire discussion moot?

+1

Just throw in a S100 spring, and your good to go

I have the 2008 version and the first thing I did was put a M110 spring in it and changed the piston and piston head to a stock TM and the anti reversal latch. The spring in it looked like it could be off the running gear of a Soviet Tank.

Our fps limits are different than yours.

Even if your limit is like 450, doesn't mean your FPS needs to be that high, if your worried about the life of your gun, switch to a softer spring, i personally don't really see a downside to low FPS

The spring isn't the issue at all. If I were to open the mechbox, I'd just install a sorbo head or nozzle pad to absorb the impact. Opening the mechbox of any stock gun is opening a can of worms. I've worked on dozens of mechboxes and the addage of "if it ain't broken don't fix it" is more true in airsoft than many other things.

If your gun is shooting amazingly well and legal, why drop it? A downside to lower FPS is that you must use lower weight BBs = less range, less flight stability, less brush penetration. I use mostly 0.25s and am moving to 0.28s.

Hmmm, true.

I guess i find that my G36 with an S90 spring shooting just over 300 FPS is much more accurate W/.25s then my stock G&G M4.


That being said, opening a stock box (especially on clones) is always an adventure

SNK when you do put in sorbos post if it quiets the gun, my JG M4 dosn't get gamed that often so I am not worried about it being damaged yet. Its at about 400fps and I do think it needds the sorbo but I wanna know if it quiets it as well?

Sorbo quiets the gun quite a bit, if u get both the MASK and the Sorbo on the cylinder head u get a quiet Pfft sound rather then the whack sound. Theres a very noticeable difference and most the sound only comes from the motor.

Oh sweet! That means I won't be found!!! Ha ha!

i have a 2008 m4 sir, im running a 11.1v lipo, and have 15000+ bb's through it without a problem. very reliable so far.

we'll just listen for the motor whine then.

:confused:

woooooo

Nova put a sorbo in one of my old G36s. It does soften the sound a bit. I actually didn't like it that much as it made the report of the gun sound strange. I kind of like the "rat-a-tat-tat" of a regular piston/nozzle head slamming.

That sound is impact, Impact is obviously bad for mechanical parts. I know what you mean though. The thud is nicer, I'm pleased with my sorbo though. Gives me a little piece of mind even though I'm running a V3

400 FPS Ratings
 

:confused: Is a bit conSCREWD(cause that is what will happen to YOU !) :banghead: I purchased a JG SR 25. It shot 395FPS. My gun tech told me to detune it right away because the stock gears can't take it and brake, not just brake but tear up the gear box as well. He had exactly the same gun, it broke horribly very soon after he got it. Lessons learned on some one else's dime or what. Then I began reading reviews, and all the 400 FPS JG SR 25 broke very quickly after the first few uses. This is true of most guns. Have them checked by a trusted gun tech for the upgraded parts to be installed at your expense. Or doun graded so you can at least play with it for a while.

Motors batteries all need to fit into a certain formula to live. In my case it was a very short time to :infantry::x: Tyhen comaes the = :banghead:

Firstly, necropost
Second, It's not 400fps that's breaking the mechbox, it's the shitty gears. Most parts, even stock, these days can handle 400fps. But cheap gears will be cheap and break.

Even then, shimming and engagement has a huge effect on overall wear. Under-shimming is hard on the motor, wears the gears brutally, and sounds terrible, where over-shimming is hard on the teeth, risks skipping, and sounds terrible.
A good shim job combined with a good motor (esp. with a mosfet) can squeeze a lot of life out of terrible gears, so the overall lifespan of a gearbox whether tip-top or chinatastic ultimately relies most heavily on shimming and AOE correction.

As for gearboxes blowing out, the spring power is a big deal, and the quality of the shell itself has a lot to do with that, but maybe not as much as many people think.
You've got this hunk of metal and plastic (piston and piston head) being pulled back and slamming into this other hunk of metal and plastic over and over again.
Think about a Newton's cradle, only the force is always unidirectional (no back swing).

Your piston and piston head are one singular hunk of mass working together to blast your cylinder head forward as hard as they can. Your gearbox shell is keeping your cylinder head from doing that. In the best case, your gearbox shell and cylinder head will both be well-cut to mate with each other in a way which leaves very little room for the cylinder head to wiggle around when struck. Your piston will also be well cut and fitted, resulting in as little wobble as possible.
In this best case, the maximum amount of inertial force will be transferred by the piston directly forward, in a straight line, through the cylinder head (losing some due to the cylinder head's own mass/ rubber brake/ sorbo pad etc), and then bled off as stress on the gearbox's arches and reinforcements. This means that the nozzle and hopup can work independently and do their job effectively, and the gears do what they do without sharing the 'conversation' about air compression.

In a lesser gearbox, however, the cylinder head may be held only by the pins within the 'cradle' for the cylinder head, creating 'hot spots' for stress on the cradle where there are no reinforcements present, eventually causing a blowout. Likewise, if all of the stress is transferred directly into the front plate of the shell and the retention pins aren't doing any work, you'll eventually get a blowout. In the third case, where the cylinder head is of low quality/ poor matching with the shell/ made out of that gummy translucent white plastic, the cylinder head will have (or develop) play within the shell, and you'll end up with the cylinder head desperately trying to escape the punishment offered by the piston, working itself loose, causing a blowout.

When you're buying one of these systems (AEG), a failure is inevitable. A blowout is inevitable. It's only a matter of time.
When you purchase and install higher quality parts (from the outset or aftermarket), you are adding time to your 'failure clock'. Still though, you can put many more hours on that countdown to doom if even the 'worst' parts are aligned properly and cared for.
The inverse is where top quality parts are installed poorly or with too much confidence in their strengths used to justify sloppy procedures.

Top-notch (re)installation of 60% quality parts can make for a 90% gun, top-notch (re)installation of 90% quality parts can make a 115% gun.
Half-assed (re)installation of any parts reduces any gun's quality by at least 30%.

Source: bedraggled, wild-eyed rental tech.
http://www.quickmeme.com/img/c4/c446...c585c6e367.jpg

My point is, you're more likely to strip a cheap set of gears than break a mechbox shell these days.
Even the stock shells now are MUCH tougher than the old marui/CA/guarder shells.
Breaks still occur, but are far less common than they used to be.

the shells you have to be careful of are the direct marui clones and oem marui shells. The more modern shells are thicker where it cracks. I have a g&g combat machine gearbox here that's starting to crack unknown to the owner. I advised him to replace it since failure would just be a matter of time, it's already cracked through on the sides but not the bottom.

I'm tempted to put it back together to see how many more cycles it will do before giving up.

That's demonstration of my point: It's a matter of time.
Shells are much improved, but the life span one gets out of that shell will vary based on how well the internals are working together.
Many of these shells will perform into the failure (crack)+ 10 000rds, but it's always interesting to try to track and estimate/ compare catastrophic failure rates.

Part of the long goal which I carried forward was to determine the best possible combination of parts and shells vs cost. The ultimate determination was that the setting of parts weighed most heavily on the end longevity of a system, and the parts involved in that equation served to add longevity on percentage, rather than the inverse.

Edit: G&G shells were fun to track, because their 'reliability' varied widely between generations. Some wanted to remain stock, whereas some wanted to have aftermarket injections.
The longest lived G&Gs were ones who had older CA internals (the classic brass cylinder/ 'condom' piston head combo) dropped in. They still died hard though, G&G shells are nice to work in, seem to be solid, but fracture the fuck out. Must be a materials composition thing.
The near opposite is CYMAs. Goddamn crap to work in. They seem to take a lot of punishment though, possibly due to higher lead content making them more flexible?

dunno, I've seen some of the newer styled stock v2s last well beyond what you think is the life expectancy.

add proper use of sorbo and I've yet to see a vfc, lonex, KA or g&p shell crack

No argument there.
I've been running a CYMA shell with an old MASk system installed, running it hard, and it's happy.

What I've been speaking from, as stated, is a rental tech's perspective. 95% of the guns I worked on saw use and abuse that 99% of all AEGs will never see.
Still though, there's a base of observable and trackable commonality between all of these systems, and when we're talking strict longevity, we're eating my bread and butter.

Edit:
It's similar to getting a gun in where someone has slammed 10s of thousands of rounds on a LiPo through a gun which wasn't built for it, but encountered a catastrophic failure.

They didn't hit that failure point because of LiPo MaGiC, they did it because any of these structures and/ or materials have a limited lifespan. That's all I was trying to point at.

G&P 249. V2 mechbox. $450 of prometheus internals. 380fps @ 1500rpm. Zero mechbox failures in 5 years of running. This year didnt count since I havent used it.

Frank, you know your stuff, I love your posts, but you're missing the point completely.

Edit:
I'm trying to encourage people to look after their gearboxes and/ or send them off to decent techs in a way that doesn't talk down to them.

I understand. Some mechboxes last a long time with minimal work, and I'm a big fan of "upgrade it as you break it"
But in the end, the product is the same. You either spend the money as it breaks and pay a fee for your gunsmith opening the mechbox every time. Or you drop the (closer to) $300 these days and just get it all upgraded at once

Over the decade I've had two kinds of customers. The kind that come to me every year with something else broken, and the kind that I build a whole mechbox for and never see again.

It's insulting to think that you have to spend what the gun is worth on upgrades to get it to finally be sound-mind reliable, but it is what it is and I'm not fond of spending $2400 on a ptw and immediately having to spend another $400 on a motor either lol

the minimum upgrade I do these days to make it worth people's money is immediate shim, sorbo/aoe and airseal upgrades usually with a steel rack piston body. Sometimes the stock seal is just terrible, if you do one, you might as well do the other 3 since you're in there already. After that it should shoot reliably until you need a new cutoff or trigger contacts.

unless if you have shitty g&p or CA gears... then expect to bend an axle or break a gear. Even then, those are a roll of the dice how long they'll last, even with upgraded gears unless you go prommy or riot.

I'm not huge on using prometheus gears outside of LMG's. Super high quality as they may be, they're just stupid heavy.
Makes them great for maintaining full auto very efficiently, but it's really hard on the motor and mosfet doing lots of semi auto.

shs... I use that shit in everything. lol.

30 bucks for a gearset, if they break... drop in a new set. I've yet to have a set break on me and I'm up in a couple dozen sets out there in my builds with 30+rps and more than 20k rounds through guns and 0 failures.

In my experience, the SHS line was pretty damn good. Lasted well in rentals, and performed well in player guns. Well above stock part performance, to the point where they began to rival higher-end aftermarket parts, especially where they were so much less expensive.

Frank:
What's a good recommendation for a gearset that'll see a shitload of semi these days?
My MP5 needs some and I'm willing to drop dollars.

I predominately use semi only, g36 has seen about 15000 rounds this year, mostly in semi. 13:1 shs with 11.1 30C 1600mah and a lonex a1.

It's been in use like that for 2 years, probably another 10k-15k rounds last year when it pushed my p90 from my go to primary.

the p90 had similar setup but with shs 16:1s and went 2 years with the similar motor and battery, probably higher round count. An odd airseal issue developed and I'm in the process of moving parts around, that gearset is now in my mp5 with a spectre fet, 7.4 60C 4200mah battery. I need to tweak a couple things with it like put the motor from the p90 in rather than use a new motor. I'd say the shs gears would be up to your task.

+1 to that. If you want to spend more than shs, go siegetek.

~$80 on prommy gears not worth it for what you get over the shs.

Great, that's one of the few things which hasn't changed much since I was still active.
Keeping on top of brands and innovations is a lot of info to crunch unless you're actively turning over guns.

Unless the thing that you want is all the extra weight so you can get 7-9BB/mah doing full auto and essentially run your 249 off a 1200mah stick battery for an op

I'd run lighter gears for semi though, like SHS or lonex or siegetek. Wasn't particularly impressed with the quality of SHS or lonex but they seem to last. Can't argue with market review.