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sacairsoftsn00py

Snoopy's Initial Impressions on the Tokyo Marui MP7A1 GBB

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Oh, OK. I meant adding or removing material to it, or increasing on decreasing the strenght of the spring. More material or less force means the valve closes sooner, less power to the BB, more power for blowback, and vice versa for less material and more force on the spring. Basically NPAS principle but manually :P

I never done it myself but saw it referensed for some gun that I can't remember right now and it works. Might be fiddly to get just right though.

Edited by NonEx

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Modifying the floating valve only changes muzzle output. Modifying the valve knocker changes both muzzle output and blow back. I've done this on a couple 5-7's and my Detonics primarily because they were recoiling too much (more so on the 5-7) on propane/green gas and the cost of 134a is about double.

Theoretically, it's also possible to control output by placing a shim under the magazine gas route rubber with a smaller sized hole to restrict flow. Would be easier and reversible though you have to do it to all your mags.

 

How much did you have to sand down on the firing pin? How much lower of a velocity were you getting before and after the mod?

 

________

 

Got an update from echigoya...other tm mp7 is inbound...they also said that they'll get me an update about my replacement nozzle within the week.

 

I love those guys. :)

Edited by sacairsoftsn00py
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Oh, OK. I meant adding or removing material to it, or increasing on decreasing the strenght of the spring. More material or less force means the valve closes sooner, less power to the BB, more power for blowback, and vice versa for less material and more force on the spring. Basically NPAS principle but manually :P

I never done it myself but saw it referensed for some gun that I can't remember right now and it works. Might be fiddly to get just right though.

 

I did this with my M14 running HPA. With a stronger flute valve spring I was able to get 625FPS with .25s at 130 PSI and keep recoil manageable.

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How much did you have to sand down on the firing pin? How much lower of a velocity were you getting before and after the mod?

If I remember correctly, on my Detonics it took 0.35mm of material taken off to bring it down from 250fps to 230fps (propane) with the recoil somewhere between 134a and propane. Had to take more on the 5-7 at 0.45mm as the recoil was really too much and was killing it. Went from about 300fps to 270fps with recoil closer to 134a than propane.

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That would be interesting. Hmmm...modify the valve knocker to decrease gas flow....modify the flute valve to increase the gas flow towards the bbs to increase fps. That in turn should increase gas efficiency and possibly aid in reducing cool down.

 

If only replacement parts for it are readily available...I may be more inclined to do the mod.

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Simple solution for the flute valve: someone sells marui style flute valves for the VFC MP5 to limit fps, If you want to up FPS you just have to find it. Else replace the MP7 flute valve with a standard marui/WE flute valve, OR a KJW rocket valve, OR a system 7 flute valve for the glocks. All those are viable options to increase FPS.

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No real updates. I got the first part of the package from echigoya. Sadly, its the main body of the mp7 and not the bolt carrier group bits...

 

They took off the upper receiver rail...sights...stock...bcg...magazine...and rails off of it. Yesterdays tracking update says these parts just left japan. Hopefully ill have em by Saturday. Then i can hopefully game by Sunday.

 

Still waiting to hear from Echigoya about the replacement nozzle they're getting for me. :)

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Flash hider threads on counter clockwise.

 

And those two bits that look like bb flowers are inserts that allow for dry firing :)

 

Edit:

 

Just did some finalization on the custom hip pouch that I'm having made by a local tactical gear tailor. It is pretty much a drop pouch...meaning that they mount on your belt and sit low. It's not quite a subload as I did not want it secured on my thigh. It will be hanging off the side of my belt when I'm crouched. Ill see how well it performs when it gets made (probably within a week of this post).

Edited by sacairsoftsn00py

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It looks like a longer barrel will not be possible (unless the inner barrel is spec8f8cally machined to spec) as the outer barrel tapers going into the muzzle.

 

On a side note:

part2mp7.jpg

 

Second bits to my second tm mp7 gbb. I should have it by tomorrow...may be gaming on sunday...a possibility of a video review consisting of everything I have found out about this piece.

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It looks like a longer barrel will not be possible (unless the inner barrel is spec8f8cally machined to spec) as the outer barrel tapers going into the muzzle.

A lot of TM models have some kind of blockage in the barrel to keep from installing longer inners. Could always drill it out.

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Echigoya shipped mp7 into two parts so it gets through customs. Parts for toys go through. Whole airsoft guns sometimes do not.

 

Thats how you could get airsoft guns with full trademarks and no orange tip as well. Least that's how airsoft global did it for me in the past

 

---------

 

 

Everything got to me fine.

 

TokyoMaruiMP7s.jpg

 

One mag is with a buddy. Hes making me a triple hip pouch for it. Pics when it gets made. :)

Edited by sacairsoftsn00py
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Echigoya shipped mp7 into two parts so it gets through customs. Parts for toys go through. Whole airsoft guns sometimes do not.

 

Thats how you could get airsoft guns with full trademarks and no orange tip as well. Least that's how airsoft global did it for me in the past

 

Ah I should have done it the same way. I still haven't received mine, the customs here are awfully slow nowadays.

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Yeah. I didn't ask Echigoya to do that though. The first shipment I got was sent to New York first before being forwarded to California. They sent everything in tact on that one.

 

I'm sure having stuff shipped separately normally costs extra. At least it makes sense doing that.

 

On a side note, I transferred the contents of a can of 134a gas into an Airsoft Innovations Gas Can. Messed around with temperature/pressure.

 

When transferring gas into another container...the pressure equalizes at some point which stops the transfer. Cool down the container where you want the gas in..heat up the container you want the gas out of. I placed the can of 134a in hot/warm water while I placed the AI gas can in the freezer for a few minutes...then transferred gasses.

 

The reason I did this is because I use an airsoft innovations duster adapter. Its made out of plastic and constant use had resulted in it cracking in the past. I figured...transfer the gas to a container with a metal tip once or twice. That'll reduce the wear on the tip then I can keep filling several magazines.

 

One can of 250ml 134a is enough to fill about 9 mp7 magazines. I have 7 on hand and an AI gas can with plenty of 134a left in it after filling it a second time.

 

So far, I have emptied one full magazine of bbs on semi auto with 134a at about 68 degrees or so to set the hop and sight in the MP7. I have loaded the mag one more time and will be shooting it again some time.

 

One thing I can say is that the MP7 definitely has a. Thud to it with 134a. I forgot how that gas isn't all that weak as it cycles the bot all the way with some punch to it. Normally other marui gbbs feel anemic...probably one of the reasons why some people use green gas or propane on em. Not the mp7.

 

I'm curious about modifying the flute valve to increase the velocity. Down side is it will be irreversible and I risk having the gun shooting over 400 fps when used with propane after reinforced parts come out.

 

Edit:

 

For those who have access to different marui flute valves, the diameter on the mp7's is 7.02mm-7.07mm. The variation is probably due to casting marks. If there's a flute valve from other gbb model that would fit the mp7...that would be awesome.

Edited by sacairsoftsn00py

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...

 

On a side note, I transferred the contents of a can of 134a gas into an Airsoft Innovations Gas Can. Messed around with temperature/pressure.

 

When transferring gas into another container...the pressure equalizes at some point which stops the transfer. Cool down the container where you want the gas in..heat up the container you want the gas out of. I placed the can of 134a in hot/warm water while I placed the AI gas can in the freezer for a few minutes...then transferred gasses.

 

...

 

 

I'm no thermal dymamics scientist nor PhD but couldn't that potentially overpressureize the recieving container once it regains normal temperature ? :|

Ie. being dangerous or causing damage to container or magazines ?

Edited by NonEx

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I was mindful when I filled up the AI gas can. It looked like it would take two fills of 134a from the can I was transferring gas from. So when I felt that the can I was transferring from was half empty...I stopped.

 

I guess common sense isn't common (not directed at you NonEx). Sometimes I type too far ahead thinking people know what I already know. Besides, its 134a...we get temperature highs in the low to high 60 degree Fahrenheit here and lows of around 50...in celcius..thats lows of 10 and highs of 20 degrees.

 

Fyi: this is what I was transfering 134a into:

 

www.airsoft-innovations.com/products/ai-gascan-compact-filling-device

 

 

Edited by sacairsoftsn00py

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