You can break a version 3 mechbox!

[Colin_S]

Heh well this is a first for me and I thought I'd share. Was going to install a set of torque up gears into a friend's TM MP5K when I found this "gem". A clean break (at least on one side) like what you get with version 2 mechboxes...



Well I guess that's what you get when you're running a PDI 170% spring and an aluminum piston head... I have a similar setup in my MP5K so I guess I'll have to get a reinforced version 3 mechbox soon too.

[Azathoth]

From the image it looks like the gun was not very well maintained.

[Syn]

Very interesting how the break is so clean and lines up with the cylinder.
The left shell front tab looks like it pushes against the right shell front tab groove. I wonder if the right side was not only taking stress on its side but also stress from the left side shell when the left tab pushes against it.

I also wonder if the shell peices had interlocking tabs if the stress would be distruibed more evenly and less likely to break.

[mike909]

Doesnt look like the gun was ever maintained. Rust, chips, and a clean brake

[CDN_Stalker]

This wil be the third time I've seen a V3 mechbox break. First was Vondnik's G36 (lasted 300,000 hots though according to him), the second I don't remember but it was posted here, and this is number three, all the same break. Funny how 95% of breaks among V2 and V3 mechboxes happen on the right side shell. My first break in my V2 MP5 (PDI 150% spring shooting 350fps) was my stock mechbox not even 2 months after upgrading, and this was only shooting in my basement during the off season. It broke on both sides. Only time I've seen that, the half dozen I've seen since then have all been the right side shell.

Deep Fire makes a V3 reinforced mechbox, and Jugglez had them in stock for a while. Maybe he still has or can get for you. And get rid of the aluminum piston head, they are 100% useless. No idea why they still make/sell them. No idea why people buy them either (except for the loud bang factor).

[Colin_S]

Just to let those of you know who claim that the gun is not maintained, the mechbox will get dirty and greasy if you actually play. It's inevitable, guns with shiny mechboxes are those of chairsofters...

Thanks Stalker yeah I've seen broken version 2 mechboxes in the past and wouldn't use an aluminum piston head there but didn't think it would be a problem with the ver 3. Reason we're using an aluminum piston head is because the PDI 170% destroys plastic piston heads in less than 1000 rounds (tried Guarder, Systema and Prometheus). In any case going to rethink the spring/piston head configuration now, sigh upgrading a MP5K (without the use of a longer barrel) is quite difficult...

[KNIVEZS]

ouch! looks its not well maintained

[Azathoth]

Originally Posted by Colin_S

Just to let those of you know who claim that the gun is not maintained, the mechbox will get dirty and greasy if you actually play. It's inevitable, guns with shiny mechboxes are those of chairsofters...

Thanks Stalker yeah I've seen broken version 2 mechboxes in the past and wouldn't use an aluminum piston head there but didn't think it would be a problem with the ver 3. Reason we're using an aluminum piston head is because the PDI 170% destroys plastic piston heads in less than 1000 rounds (tried Guarder, Systema and Prometheus). In any case going to rethink the spring/piston head configuration now, sigh upgrading a MP5K (without the use of a longer barrel) is quite difficult...

I Totally disagree, I tear my gun down clean it at least once a month during the season, and a couple times in the off season to clean, and grease. My box and parts look nearly brand new. You can see signs of wear such as discoloration etc but you should never have rust flakes in the box.

[Colin_S]

Originally Posted by Azathoth

I Totally disagree, I tear my gun down clean it at least once a month during the season, and a couple times in the off season to clean, and grease. My box and parts look nearly brand new. You can see signs of wear such as discoloration etc but you should never have rust flakes in the box.

I certainly admire your determination. There's no real off season here, we do play in the winter if not outdoors then in. I don't know of anyone locally anyway who routinely strips their mechbox down to clean, I know I certainly wouldn't have time to clean my guns like that as I have 10. Myself I usually go in my guns only when necessary.

For the record there was no rust in the mechbox or on the shell, the discolouration is due to the lighting.

[Syn]

My mechbox has rust all the time becuase I play underwater. You guys don't play underwater? You are pussies lol.

ok seriously. Gandolf had a mechbox break the same way. I'm seriously comsidering of reinforcing the front of my v3 somehow.

[Azathoth]

Originally Posted by Colin_S

I certainly admire your determination. There's no real off season here, we do play in the winter if not outdoors then in. I don't know of anyone locally anyway who routinely strips their mechbox down to clean, I know I certainly wouldn't have time to clean my guns like that as I have 10. Myself I usually go in my guns only when necessary.

For the record there was no rust in the mechbox or on the shell, the discolouration is due to the lighting.

It helps that I only own 1 AEG and a single GBB. I usually tear down my GBB weekly as I basement plink to the tune of about a bag a week.

I also reuse said BB's. Had the occasional fart in the pistol.

[amano999]

This is my mp5k and no I don't go into it at all or clean it very often :P

Usually me or my wife use it outdoor and it's seen allot of play.

[IRONSIGHT]

I'm wondering if the reason they all seem to break in that spot (V2 anyways) may be the way people dissasemble them. Every person I've seen taking one apart tends to remove all screws and then pry open the box starting from the rear or from the bottom where the motor mounts. This can put stress on that point when done repeatedly over time. I try to open the front first as it also helps prevent everything from flying everywhere. I'm not saying this is the only reason, but it could be a part of it. Whatever spring or mechbox type you want to use, a silent piston head & cylinder head will definately help cushion the blow and give your mechbox a longer life span.

[manchovie]

Originally Posted by KNIVEZS

ouch! looks its not well maintained

looks fine to me, take a picture of anything up close like that and with a flash and it'll look gross. besides, how would dirt make the box break anyway? colin's documenting an interesting find and you dudes are chiding him for bad maintenance based on made up facts and improvised evidence? puh-lease.

[MadMax]

Tearing down a gearbox too frequently results in stripped holes in plastic and metal parts. There is not rust on the mechbox. It's aluminum and does not oxidize the same way that ferrous materials do.
Is there any evidence of a preexisting casting flaw that maybe have initiated the cracking? Accumulate enough repair history and you're going to get to see some obscure failures.