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sacairsoftsn00py

Snoopy's Initial Impressions on the Tokyo Marui MP7A1 GBB

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Well, yeah. Like I said I an no genious but I figured it isn't without it's implications, and perhaps that information should be shared as well so that people who know less than you and I don't have accidents... So, just glad we got that down in text form so people know!

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No doubt dude.

 

70F. 134a. 140rds w/ bolt locking back on last round 1 second shot interval. 5 min rest time after a full mag is spent.

 

Btw, a full load of mag is 40 rounds. After three magazines, I loaded the mag with 10 bbs on two different occasions as I felt that it was starting to slow down some. It actually went up to 144 rounds. Just that it wouldn't lock on the last 4 rounds before using up the entire charge.

Edited by sacairsoftsn00py

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Seems the busted nozzle on propane isn't an isolated case. Another one reported at ASF in Minnesota:

http://www.airsoftforum.com/board/TM-MP7A1-Busted-BBU-CYlin-t258279.html&pid=18678675?do=findComment&comment=18678675

 

That one broke in EXACTLY the same way as the one here, and doesn't have the bubble from casting.

 

Well, looks like this thing can't handle green all that well...

 

Snoopy's

20121109_133020.jpg

vs this other guy's:

8191123041_9a64aef93a_b.jpg

Edited by kenxin

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Just buy another one. Lol.

 

134a for me until they come out with a reinforced nozzle.

 

The nozzles are thick...just that on these two guns...the nozzles weren't able to take it.

 

If/when guarder comes out with a nozzle....green gas/propane will be my preferred propellant of choice.

 

 

Good find renegade :)

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It does.

 

Long term reliability is not guaranteed with. Of higher pressure gas at warmer temps.

 

The one in MN busted while firing at 80 degrees...approximately 128 psi with propane. 134a reaches that pressurr at 100 degrees or so.

 

Not sure if temps reach that high in japan. If it does, the nozzle should have been able to take that kind of pressure on 134a. Then again who knows...I mean how many people play at 1pp degree temps?

 

Still...nozzles breaking is a temporary issue until reinforced nozzles come out. When they do...problem solved. Hopefully everything else holds up.

 

The nozzle issue isn't new. A lot of gbb's suffer from it at some point. Some a lot quicker than others.

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Hmm perhaps I chose the words wrong. The point I was trying to make is that this second case broke in the exact same way without the presence of the air bubble.

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Like I asked previously, even if the PSIs are the same for the two gasses at different temperatures, do they expand and react the same when released from the magazine, ie. is the expansion as volatile for 134a as for green gas at the same PSIs. I don't know, but it might very well be a factor.

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I'm I think psi's play a great deal. Its most likely the main factor in breakages...considering it takes a split second for things to happen. What other variables could there be other than how quickly the gas expands once outside the magazine? Anyhow..that question is reserved for the technical section...or for those who like to find out everything...wish I have an answer for you but I don't.

 

And yes, the other nozzle broke in a very similar way

It probably wont be the only breakages that will happen. Bet the next account of nozzle failure will occur in a similar fashion. Higher temp, green gas/ propane, same breakage area.

 

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You're the one who's telling everyone the two gasses PSI's (in your opinion also force of expansion when released) at different temps is equal and that it should be fine as long as the PSIs match up at any given temperature, yet you don't know if this is true or not ?

 

Isn't the PSI just how much pressure the gas is under in a stored container at a given temperature, not how much force it expands to once released ? I think the boiling point is the other major factor that I am referensing. But I don't know, so I will leave it at that, but I think PSI for PSI is a bit too easy of a comparison to say it is a 1:1 ratio in force exerted.

Edited by NonEx

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As a KSC Taiwan MP7 owner I am enjoying this thread. I was going to pick one of these up as well but it's already too cold to use GBB with 134a. Interesting to see the two failures reported. I might grab the images and hit up Marui on FB or twitter to see what they have to say. Maybe a chat with the boys at Echigoya or with ORGA to see if they are experiencing similar issues... however, it is nearly impossible to get propane here in Japan, so my guess is that 95% of these sold in Japan will be using 134a, so I don't think it will be as wide spread a problem.

 

On another note, if anyone needs replacement parts, feel free to contact me and I can order from Marui directly. Echigoya has told me in the past that Marui is often willing to send parts directly to customers faster than to shops.

 

How effective is the hop on this thing? Standard Marui quality?

 

Also looks like PDI (X-Fire) has already got a tight barrel in for this.

http://www.x-fire.org/e.index.htm

  • Like 1

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You're the one who's telling everyone the two gasses PSI's (in your opinion also force of expansion when released) at different temps is equal and that it should be fine as long as the PSIs match up at any given temperature, yet you don't know if this is true or not ?

 

Isn't the PSI just how much pressure the gas is under in a stored container at a given temperature, not how much force it expands to once released ? I think the boiling point is the other major factor that I am referensing. But I don't know, so I will leave it at that, but I think PSI for PSI is a bit too easy of a comparison to say it is a 1:1 ratio in force exerted.

Ok.

  • Like 1

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:D KWAs still a tank then!

If memory serves, the first KSC release had the same nozzle issue too. Give it time, TM will iron it out.

 

Regarding reporting breakages like these, it's not so much as to cause alarm or even to tarnish the companies name, it's simply to put it out, that it has happened and future buyers might expect it given the same conditions. Plus the more any problems are published the easier it is for after market companies to pick them up and make reinforced replacements. In some cases it's the parent company itself that makes design or material changes to make better their product.

 

edit:

To NonEx, you're right that there's more to gasses than raw PSI. There's the rate of expansion/decompression which is very different between the two. However I doubt there's anyone here with the tools or access to a laboratory that can measure that so PSI will have to make do as a general guide regarding how much abuse gas guns can take.

Edited by renegadecow

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And that's just it. Countless of users feed their TMs with propane without a problem and while it's beyond what's recommended in the manual it's often taken for granted. Put the MP7 in the hands of someone with that mind set then have it break and they'll have the impression that they bought an inferior product. Let striking images do the work because quite frankly not many kids these days even go through the manual.

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I did a quick chrono: 10 shots fired indoors with 'Cyber Gun Extreme Blowback APS3' gas using 0.20g BBs: Highest FPS 343, lowest: 323.

Fired less than 100 rounds on that gas and no damage to the nozzle so far, I'm not going to risk it, so going to change to 'duster' gas until upgrade parts are released.

 

I've tried the Umarex/VFC suppressor, the flash hider has the wrong direction thread, and unfortunately the suppressor does not mount properly to the TM flash hider, guess I will have to wait for an after market one as-well :(

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I did a quick chrono: 10 shots fired indoors with 'Cyber Gun Extreme Blowback APS3' gas using 0.20g BBs: Highest FPS 343, lowest: 323.

Fired less than 100 rounds on that gas and no damage to the nozzle so far, I'm not going to risk it, so going to change to 'duster' gas until upgrade parts are released.

 

I've tried the Umarex/VFC suppressor, the flash hider has the wrong direction thread, and unfortunately the suppressor does not mount properly to the TM flash hider, guess I will have to wait for an after market one as-well :(

 

The Angry Gun version works.

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