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sacairsoftsn00py

Snoopy's Initial Impressions on the Tokyo Marui MP7A1 GBB

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I have been following the chatter about the Tokyo Marui H&K MP7A1 GBB since word got out that Marui will be releasing it. Finally, I have one in my hands to review. Big thanks to Echigoya-Guns of Japan for getting me my order in a timely manner.

 

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This is my quick write up.

 

The Marui H&K MP7A1 comes with the flip up front and rear sights installed. The box has a separate slot for the 40rd magazine. The box also has a compartment for BBs, and the included 14mm- muzzle adaptor for suppressors or tracer units.

 

A lot of people already know that the dimensions of the gun are similar to the KWA/KSC version of the MP7A1. The front and rear sights are windage and elevation adjustable in both flipped up for SMG use, or flipped down for pistol-sight use. This allows for more precise aiming in either mode.

 

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As far as the finish goes, Marui uses its typical ABS plastic polymer finished in matte black with a slight texture to it. The paint used on the selector lever is not bright red (like the KSC/KWA version), instead...its more subdued. The H&K trademarks are present on the grips with the caliber of the RS counterpart engraved on the left side (on the KWA version, the engraving shows 6mm for the caliber).

 

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*Do note that the marks around the pin holes are casting marks. The other side has them to. It is not a crack on the material

 

The fire controls are made out of metal. Metal parts include the front and rear sights, the rail system, trigger, select fire lever, bolt catch release lever, magazine catch, retractable stock bars, much of the bolt carrier (part of it is plastic). Everything is well fitted. The joints are well mated and screwed together with phillips screws (none of that .9mm screws that KWA uses). The 40 round magazine is made out of metal for the most part...only the bb follower and feed lips are plastic. Upon inspection, I noticed that the TM MP7A1 GBB has a metal internal casing which houses metal internal parts. This metal casing also reinforces the pin holes that hold the back of the MP7 (The KSC/KWA version does not have any reinforcement around the pin holes which is why they do not hold up as well as they could with powerful gasses at higher temperatures)

 

The hop up can be accessed only if the magazine is taken out. With the MP7's magazine out, you have to push the trigger forward. This pushes the bolt carrier back and reveals the hop up dial. The hop up dial rotates forward and back to adjust the hop. This dial is securely in place and is very very tight. It takes a little bit of coaxing for it to move which is what you want as your adjustments will be more precise and will stay securely in place.

 

At approximately 72 degrees Fahrenheit and the hop turned off, my Xchortech x3200 chronograph was registering .20g BBs around 335 FPS with a +/- 2 FPS deviation over 10 shots at one second intervals using propane. Rate of fire as expected was between 15-16 RPS. For those wanting to get a higher FPS output for the TM MP7, be on the look out for tightbore barrels. Stock barrel bore is 6.08mm with a length of 145.5mm. A tighter bore and longer barrel will definitely increase the power of the Marui MP7A1 significantly in addition to better accuracy, precision, and range.

 

There are a few videos on youtube showing how accurate the TM MP7A1 is. As far as range goes, expect ~200 feet of effective range from this gun.

 

Felt recoil of the TM MP7A1 GBB is definitely more than that of the KWA MP7A1 GBB. The KWA version is more crisp but the TM version has more kick.

 

Other things of note:

* The stock can be pulled out and set into three lengths of pull.

* The selector lever clicks into place on safe-semi-full auto settings.

* The trigger's mechanical safety catches some when pulling the trigger back. A little filing down with a hobby file solves this. This need not be done. IMO, it'll wear down on its own...I just don't want to wait for it to wear down naturally. Doing this mod allows for a much smoother trigger pull.

* The plastic feed lip of the magazine holds the bbs securely. The plastic feed lip ensures that the bbs do not get gouged when it gets chambered where as you risk having bbs damaged with metal feed lips. Gouged bbs result in poor accuracy.

* The magazine's BB follower has to be held down when loading BBs KSC/KWA magazines have BB followers that lock down into place.

* The magazine needs to be filled properly. Having BBs positioned incorrectly may keep the magazine from feeding the BBs properly. Ive tried it on a couple of mags and not having the bottom most BB properly positioned resulted in the bb follower staying down (preventing the bbs from going up).

* The back of the TM MP7 where the bolt carrier hits has a spring in place. This spring absorbs the shock from the bolt carrier hitting it. The KWA version uses a rubber pad to buffer the impact.

* The nozzle return spring on the TM MP7 is the push type where as the KSC/KWA uses the pull type spring (which are prone to snapping).

*The back of the bolt carrier has an o-ring that absorbs the shock from the nozzle returning back to battery. This o-ring however pushes the bolt carrier back which results in a 1mm gap between the front of the bolt carrier and the front of the ejection port.

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At the moment, I don't have very many photos snapped of the TM MP7A1 GBB Available. When I do, I will post additional ones. Unfortunately, I may not be able to add it into this entry.

Edited by sacairsoftsn00py

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Nice.

 

What about gas efficient?

Can it dump whole magazine in full-auto with green gas?

 

And want to know weight of complete bolt carrier.

 

It can dump a whole mag with green, though it does have a bit of cool down towards the end.

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Less than 200 rounds with propane at sub 75 degree temp. Cracked nozzle.

 

Guess im buying another one to run with duster gas while waiting for reinforced nozzles to be released.

 

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Taking apart the nozzle assembly led me to this discovery...the flute valve has a post running through the middle. Normally tueres just a pointy hump. The one on the mp7 nozzle is probably around 6mm. This was probably done to restrict the flow of gas which would in turn keep the fps down.

 

Taking the nozzle out requires a small phillips screw driver (a no. 1) and a T20 torx driver (or screw driver bit). Replacing the nozzle will be a breeze. I'm not quite sure why the nozzle broke so quick. I may have an idea...its possible that the hop bucking grabs onto the loading nozzle a bit much. Paired with a faster blowback...added stress gets put on the loading nozzle. Still, my caliper read ~1.35mm in terms of how thick the cylinder walls are on the sides. I would imagine that the breakage area would be no thinner than that.

 

Airsoft Surgeon/ Guarder...please save me! Lol.

 

Super glue is currently curing. Im switching over to duster gas after this while HeadOn Tactical is working on my MP7 hip pouch. Im also waiting on them to restock multicam cordura fabric so my 6 cell MP7 chest rig can get started.

-------

 

Edit:

Couldn't wait for reinforced nozzles to be made...I will game with the TM MP7 GBB regardless of what gas I have to use. Propane will have to wait. Duster gas it is.

 

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Edited by sacairsoftsn00py

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Im out of duster gas. Lol!

 

I don't really care...I just really don't like waiting.

 

In a month or two...someone will be releasing a reinforced nozzle. Until then...the next tm mp7 gbb im getting better hold up with duster gas...

 

Should be fine as highs where im at reach around 75 degrees in the afternoon...just that its getting cooler now. When I get to games where weather dips to 50 degrees...then just switch to my marui scar-h.

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Who knows. I wanted to use propane cause its less affected by cooldown and its the only thing I had. I didn't think that 70ish degrees would still be too high a temp to run the gun safely. I guess it was...

 

I'm not worried about it. Nozzles will be around eventually...plus I'll have another TM MP7 to tide me in. Just run the one coming in with duster gas.

 

I'll run propane when the nozzles come out.

 

I like the recoil and what not but I actually would like a lighter bolt carrier. It'd make the whole system more efficient. A cnc'd aluminum bcg would be awesome. Lower recoil...higher rate of fire...better accuracy. Yup...I want one.

Edited by sacairsoftsn00py

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Aaah... That sucks man, but I hate to say I told you so :o

Not you specifically but, we had a long discussion about this in this thread so. Yeh... TM = 134a if you want it to last.

 

Hope you get a spare or that reinforced nozzles come out ASAP.

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I'd imagine that a re-inforced nozzle will be up for grabs pretty soon.

 

My MP7 seems to be doing just fine - and at a higher temperature too (26-28C).

 

Odd.

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Yeah. I knew that running propane will cause quicker wear and tear than if I were to use 134a. Some Marui gbbs handle propane like a champ though. I didn't think the nozzle would go so quick. Dark Lite seems to have better luck than I do in that department. I mean the nozzle is thicker than pistol nozzle walls. Its odd that this one broke so quickly.

 

Yes, I have a chart in my phone on pressures for propane, 134a, and 152a gasses at different temps. I posted that chart on a different section...I should post it on here as well as an fyi thing.

 

Oh well...that means I get to tinker with it more...not feeling extra adventurous to take down the whole thing yet. Who knows...for now, nozzle replacement (when it becomes available) will be a breeze. That much I know.

 

You could take down the bolt carrier group and nozzle assembly and replace it in a few seconds. Its almost as simple as replacing a glock's nozzle :)

 

Edit: pressure chart for propane and duster gasses...

 

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I would imagine that ideal operating temp for marui gbbs would be around 70-80 degrees Fahrenheit. Simply compare the pressure from that temp with 134a and the conditions/gas you're putting the gun through and get an idea as to how hard youre pushing your gun past/below what pressures it was built for.

 

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Edited by sacairsoftsn00py

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It is not wear, its a fracture.

 

Gas expansion doesn't cause fractures like this. This is a localised impact fracture. Figure out where the forces are redirecting to then you may find out how to prevent/buffer it.

 

The hop grabbing the nozzle should not cause this issue in that area.

 

There are 4 things which could create the impact:

 

The flute valve impacting on the insides of the blowback unit

The stopper that pulls the nozzle backwards during the firing cycle

The impact of the nozzle as it returns rearwards (determined by the return spring tension).

The impact of the bolt returning forward having stress on the blowback unit.

 

Since there is the 1mm gap issue with the bolt not fully returning forward, is most likely the cause, though that sort of breakage is consistent with the flute valve impact.

 

I won't know until I get my hands on one.

Edited by 3vi1-D4n

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The term wear and tear was probably loosely used for you.

 

The flute valve weighs less than one gram most likely. Would that be enough to damage the nozzle after less than 200 rounds? The term "less than 200 rounds" that I used isn't super accurate. It was more like..less than 70 cycles which included the dry firing. I put about 20-30 bbs through the gun as I can't really fire that much at work (family business).

 

The 1mm gap is from having the o-ring pictured. That o-ring cushions the nozzle from when it returns to battery. It may also be the area (acting as a buffer)that stops the whole bolt carrier group...between that and the front of the nozzle where the breakage occurred. I may remove that o-ring and see how far forward the bcg moves forward...im sure that o-ring is there for a reason.

 

Super glue didnt hold up as expected (even with just 5 shots at 72 degrees with 134a)

Edited by sacairsoftsn00py

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I wouldn't underestimate the impact forces on the flute valve. Having seen those WE stainless steel flute valves break I wouldn't disregard the possibility, even though unlikely.

 

The O-ring may cushion the rear end on the return, but it will not cushion the front from the impact.

 

To fix it you can try plastic welding or a low temperature soldering iron. Its broken what have you got to lose? :P SO long as you find the stress point.

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Im not gonna try to fix the nozzle. Im waiting on the other mp7 I ordered. Lol!

 

What I was thinking was that the nozzle stayed forward (cause the bucking was grabbing it a little too much). As the bolt carrier moves back, it hammers into the nozzle.

 

Should I post a photo so you get a better idea as to what I think happened?

 

Seeing as my nozzle is the first documented case to a broken nozzle...it might be that it was an individual/isolated occurrence. Who knows...maybe the shell holding the bucking in place has it so it squished the nozzle a lil more than it should.

 

To those who have the mp7 already...you guys know how stiff it is to pull the hop unit back (by pushing/pulling the trigger forward). Well, with the bolt carrier being pulled back by the charging handle...the nozzle stays forward and stuck into the hop chamber assembly...at the end point of the nozzles forward most position, the nozzle was able to pull back the hop unit by 1-1.5mm. While that might not seem much...it takes a good amount of force move te hop unit back. That means the nozzle gets hung up at front as the lart of the bolt carrier slams into part of the nozzle.

 

Sorry about the format of this entry...im typing away on my cell phone.

 

 

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Yeah I know what you are saying...I did highlight this as a possibility:

 

The stopper that pulls the nozzle backwards during the firing cycle

 

The fact is that the gripping of the hop rubber to the nozzle is a good thing. It ensures that there is minimal gas loss from the blowback unit to the breech. If its too tight then the bolt would not return home fully forward. And I know marui with their tight tolerances would not make that mistake.

 

There should be something on the Bolt carrier that pulls the bolt head back after the bolt travels backwards a certain amount, where is that hitting the bolt/blowback unit? On the WA/inokatsu M4s and the 1st gen GHK AKs thats where the weakness is, though on the VFC M4 its the bolt carrier which holds the stopper that couldn't take the stress.

 

What I am trying to get at is that there may be solutions which can help solve this aside from more strengthened parts which at times can cause more problems.

Edited by 3vi1-D4n
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Im thinking that while the nozzle tip stays forward...this part get hammered back til the whole assembly gets pulled all the way back..

 

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The nozzle is at the forward most position here which means the bolt carrier is pulling back the nozzle from its forward most position at this point...

 

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Excess pressure doesn't have much room to "blow out. Works for lower pressure gas...not so much with higher pressure ones...maybe?

 

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