Tokyo Marui M870 Tactical Gas Tri-shot Shotgun- picture, text and video review

[Stuey]

How many mags have blown up again?

 

Exactly...

 

Use it per manufacturer specification...if you have problems then...contact the retailer you bought the gun from.

 

Having issues cause you used a higher pressure gas? Who put green gas/propane in it ..you. who's to blame? Marui. Lol

 

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If these parts are deforming under the pressure of propane, then shame on Marui for such poor engineering. The standard rule is that a gas container should be able to withstand three times the pressure it's rated for. If the tank is meant to be used with HFC-134A, which is a little over 80PSI at typical room temperature, then it should be able to go up to 240 PSI- and that's double what propane is under typical UK/US use conditions.

 

Deformative expansion over time can lead to structural failure and possibly kaboom. For a part to risk this at just over its specified operating pressure is extremely unimpressive.

 

[CatgutViolin]

How many mags have blown up again?

 

Exactly...

 

Use it per manufacturer specification...if you have problems then...contact the retailer you bought the gun from.

 

Having issues cause you used a higher pressure gas? Who put green gas/propane in it ..you. who's to blame? Marui. Lol

 

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HFC-134A can easily get up to 110-120PSI on a hot day, same as propane at room temp. A gun that can't handle anything over its intended pressure is poorly designed, simple as that. It's not like we're talking about running unregulated CO2 and complaining that it can't handle 850PSI, it is absolutely reasonable to expect a decent safety factor.

 

Whether there are documented cases yet of them blowing up, I sure wouldn't want to be running that risk with my face up against a plastic stock containing such a gas tank. And I'd be concerned about what these guns will look like in two or three years' time.

Edited September 29, 2013 by CatgutViolin

[sacairsoftsn00py]

If you are mindful of your equipment....like when to use it and what not. It should be fine in 3 years. If the gun is left with the gas tank in it under the sun on a hot weather. ..do expect for something to fail gas tank wise...externally...

 

I'd say that to please everyone about the mag not being able to take much higher pressure gas...I could argue that marui should have made the walls thicker. Then maybe it can shoot say. 80 shots with 134a and pissibly 15-30 rounds per charge on green gas. Or...maybe tm could have put an additional hole for a blow out valve in the tank.

 

If by chance marui feels the need to adress tank expansion...they could change the material, add certain features, or thicken the walls of the mag. Hopefuly the rest of the components hold up.

 

 

 

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[Baddbaz]

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The Pressure Systems and Transportable Gas Containers Regulations 1989

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1989 No. 2169PART VRegulation 16

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Status:This is the original version (as it was originally made). This item of legislation is currently only available in its original format.

Design standards, approval and certification

 

16.—(1) No person shall–

(a)supply for the first time;

 

(b)import; or

 

©manufacture and use,

 

a transportable gas container unless the conditions specified in sub-paragraphs (a) or ( of paragraph (2) have been met.

(2) The conditions referred to in paragraph (1) are–

(a)the container has been verified (either by certificate in writing or by means of stamping the container) as conforming to a design standard or design specification approved by the Executive–

 

(i)by a person or body of persons corporate or unincorporate approved by the Executive for the purposes of this paragraph, or

 

(ii)in accordance with a quality assurance scheme approved by the Executive; or

 

(b)the container is an EEC-type cylinder, that is–

 

(i)there is an EEC Verification Certificate in force in respect of it issued by an inspection body which, under the law of any Member State, is authorised to grant such a Certificate for the purposes of the framework directive and the separate directive relating to that type of cylinder, or, in the case of a cylinder not subject to EEC verification under any of the separate directives, it conforms to the requirements of the framework directive and the separate directive relating to that type of cylinder, and

 

(ii)it bears all the marks and inscriptions required by the framework directive and the separate directive relating to that type of cylinder.

 

(3) Any approval under this regulation shall be by a certificate in writing, may be made subject to conditions and may be revoked by a certificate in writing at any time.

(4) Schedule 5 shall have effect with respect to fees for approvals under this regulation.

(5) In paragraph (1)(a) the reference to supplying a transportable gas container for the first time is a reference to supplying an unused transportable gas container, that is, one from which a relevant fluid has not been used.

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This may throw a spanner in the works for marui gas containers / tanks in the uk

Edited September 29, 2013 by Baddbaz

[Baddbaz]

Propane tanks, regardless of size store propane liquid until it is used as either a liquid or vapor. All propane tanks are subject to rules based on safety and can only be filled to about 80%. Many people believe that propane tanks and butane tanks are the same but propane pressure is much higher than that of butane. This means propane tanks are subject to higher pressures and the two types of tanks are in fact very different and cannot be filled with either of the two LP Gases. Propane tanks are for storing only propane. This section covers related subjects such as: t

 

Taken from a later page in the same document / laws ..

I would stick to 134 a use with this gun

Edited September 29, 2013 by Baddbaz

[onizuka-gto]

If you are mindful of your equipment....like when to use it and what not. It should be fine in 3 years. If the gun is left with the gas tank in it under the sun on a hot weather. ..do expect for something to fail gas tank wise...externally...

 

I'd say that to please everyone about the mag not being able to take much higher pressure gas...I could argue that marui should have made the walls thicker. Then maybe it can shoot say. 80 shots with 134a and pissibly 15-30 rounds per charge on green gas. Or...maybe tm could have put an additional hole for a blow out valve in the tank.

 

If by chance marui feels the need to adress tank expansion...they could change the material, add certain features, or thicken the walls of the mag. Hopefuly the rest of the components hold up.

 

 

 

Sent from my Samsung Galaxy S4 using Tapatalk 2

 

 

I have to say, there is considerable dispute into how many shots the current tanks can give, my own experience with imne, has been over 30 shots on one full tank so far. Granted i'm not so sure personally how many i can get from my tank under green gas as i stopped after that (ran out of time).

 

However you can see for yourself how many shots it is capable of, just watch the video below by KhanSeb:

http://youtu.be/dwA1oIdLXMM?t=10m20s

 

He managed to get 100+ shots in 3 round burst and 60+ shots in 6 Round burst.

[Aod]

If that legislation was applied to Airsoft, every green gas cannister in the UK would have to be removed from sale as none of them are certified in any way.

 

What everyone needs to understand is that there is a finite amount of "play" in the walls of the gas-magazines, once they've expanded out a given amount, there's no reason to suggest that they'll keep expanding to the point of failure (especially given that there are no reports of failure).

 

Stop worrying and enjoy your increased gas-capacity due to the larger magazines

[Baddbaz]

Its not so much the legislation its the actual guidelines included that carry the worrying information . Ie , that no tank containing propane should be more than 80% filled at any time , to allow for the gasses natural expansion and instill a safety margin for any containers expansion . In canada they have already banned the use / sale of the kits/ valves used to fill Airsoft mags / tanks with propane .

 

Just for the record ,That legislation does apply to the uk to include all propane containers be they Airsoft , camping , household or industrial use .

The saving grace is that propane fires / explosions are very rare and usually caused by excessive heat Causing over expansion of the vessel or a naked flame in the vacinity of a damaged tank .

I am wondering if filling the tank to full capacity with propane / green with no movement / allowance for the gasses natural expansion is causing the deformation of the marui tank .

Some people will leave propane / green in the tank to save their seals etc , 134/144 would be a much safer bet for magazine / tank storage purposes .

I did not make this post for a panic effect I made it to enable newbies or people with no knowledge of safe gas handling / storage awAre of the safety aspects of using propane gasses. . Especialy the storage and safety guidlines regarding external heat sources and refilling propane containers

As aod has said there have been no reports of tank failure as of yet , but sensible and safe use would be reccomended ,ie no smoking / filling tanks near ignition sources etc would be highly advisable . Also do not store your guns , tanks , mags above or near heat sources . Ie radiators , fires etc in your house / home .

Edited September 30, 2013 by Baddbaz

[sacairsoftsn00py]

I have to say, there is considerable dispute into how many shots the current tanks can give, my own experience with imne, has been over 30 shots on one full tank so far. Granted i'm not so sure personally how many i can get from my tank under green gas as i stopped after that (ran out of time).

 

However you can see for yourself how many shots it is capable of, just watch the video below by KhanSeb:

 

He managed to get 100+ shots in 3 round burst and 60+ shots in 6 Round burst.

I get over 100 shots on a full tank of 134a. I have 11 shells which ive shot out without needing a full charge.

 

You could also watch the rapid firing with the extended mag by the gun engineer guy or something like that...over 100 shots per full charge.

 

If you re-read my post, I mentioned the gas tank being made with thicker walls...meaning decreased internal volume for holding the propellant...thus the lower estimate of shots per full charge of gas.

 

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[steelfallenangel]

Should have used 134a.

 

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Isn't there a new law in japan that is forbidding them from using 134a gas? I thought I remenber seeing that somewhere on this site.

Guess I'm glad I didn't jump immiedatly to buy one of these. Not that I don't still want one but these early adopter stories are pretty scary.

[DrAlexanderTobacco]

Isn't there a new law in japan that is forbidding them from using 134a gas? I thought I remenber seeing that somewhere on this site.

Guess I'm glad I didn't jump immiedatly to buy one of these. Not that I don't still want one but these early adopter stories are pretty scary.

134a is IIRC banned worldwide now, as it contains CFCs. 144a is the substitute.

[Rob15]

134a is IIRC banned worldwide now, as it contains CFCs. 144a is the substitute.

R-134a isn't a CFC, it was the replacement for R-12 which was a CFC. 144a is just a name Abbey Supply have given to a R-134a alternative/replacement for sale in Europe to make it more recognisable to airsofters as a low pressure gas, what the actual name of the gas is I don't know.

 

That said R-134a is at the very least being phased out worldwide, even if it's not banned the drop of industries using it will cause it to become uneconomical to produce and even Japanese airsoft manufacturers will have to start using one of the replacements.

 

On another note, everyone is talking about deformed tanks but has anyone yet had one leak or taken the end plate off one to see what the construction is like inside? It would be interesting to see how thick the walls of the tank actually are compared to a regular gas magazine with shorter sides that would be less prone to deforming.

[Aod]

R-134a isn't a CFC, it was the replacement for R-12 which was a CFC. 144a is just a name Abbey Supply have given to a R-134a alternative/replacement for sale in Europe to make it more recognisable to airsofters as a low pressure gas, what the actual name of the gas is I don't know.

 

That said R-134a is at the very least being phased out worldwide, even if it's not banned the drop of industries using it will cause it to become uneconomical to produce and even Japanese airsoft manufacturers will have to start using one of the replacements.

 

On another note, everyone is talking about deformed tanks but has anyone yet had one leak or taken the end plate off one to see what the construction is like inside? It would be interesting to see how thick the walls of the tank actually are compared to a regular gas magazine with shorter sides that would be less prone to deforming.

Suggesting that airsofters take a logical and methodical approach to something rather than a knee-jerk reaction? Who are you and what are you doing in the Airsoft Community?!

[Stuey]

144a can't exist as a chemical, so as Rob says it's just a name Abbey have given to whatever they're selling instead of 134a now.

[Wingmann]

On another note, everyone is talking about deformed tanks but has anyone yet had one leak or taken the end plate off one to see what the construction is like inside? It would be interesting to see how thick the walls of the tank actually are compared to a regular gas magazine with shorter sides that would be less prone to deforming.

Can't say anymore. I read this thread and threw my gas tank out of the window!

[Baddbaz]

Can't say anymore. I read this thread and threw my gas tank out of the window!

Did it deform any further when it landed ? Lol

[Stuey]

Its not so much the legislation its the actual guidelines included that carry the worrying information . Ie , that no tank containing propane should be more than 80% filled at any time , to allow for the gasses natural expansion and instill a safety margin for any containers expansion . In canada they have already banned the use / sale of the kits/ valves used to fill Airsoft mags / tanks with propane .

 

If you just connect a propane bottle to an empty container the pressure will equalise and the flow will stop before the container is 80% full. If you do refill those Coleman tanks from a big propane bottle the flow stops when they're half or less full - if you want to fill them to the same level as when they were new, you have to chill them or manually open the blowoff valve to lower the pressure in the Coleman tank to allow more liquid propane to enter. As such, you can't fill an airsoft mag completely just by gassing it normally - which is a good job, that would be dangerous (as you said). You could potentially fill it completely if you chilled the mag beforehand, but no one does that. The current design stops filling at a safe level by itself.

 

Also, green gas is propane so if they allow green gas in airsoft mags but ban propane that's retarded.

Edited September 30, 2013 by Stuey

[lacanuck24]

So to get back on topic more bout the gun than the gas, what are people using or thinking about using as a feed tube extension? I'm itching to make it longer and I know viagra isn't the answer.

[onizuka-gto]

aluminium tubing, internally tapped so it can be screwed on?

[lacanuck24]

Was wondering more if there is anything off the shelf that might work since I have difficulty communicating with the locals

[K.A.M.P.H.U.N.D.]

G&P's tube has the same outer diameter as TM's inner diameter.

Some work left though.

 

 

 

[Wingmann]

Did it deform any further when it landed ? Lol

I didn't dare to look after the secondary explosions.

[Inari]

I didn't dare to look after the secondary explosions.

OMG you too?! I'd post pictures, but the shrapnel destroyed my camera...I nearly died!!

[onizuka-gto]

I didn't dare to look after the secondary explosions.

 

 

What a waste.....at least you could of taken it apart so that we can have a look inside.....   

[Baddbaz]

Could have been worse !

 

 

 

 

 

 

Could have been my one .........