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


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Afternoon guys.   This morning I was very lucky to receive my brand spanking new Tokyo Marui Remington M870 Tactical, from the good folks over at Redwolf UK.   This is a text/ video review for now

Chopped the barrel and added an ATI heat shield- quite happy with the result!          

TM issues a product recall?   In other news, pigs spotted flying over Hampshire, Peter Mandelson is a force for good, David Cameron gets on his bike, Nick Clegg tells the truth and the Ministry of D

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Well 100GBP is about 180USD so 60$ is not a lot cheeper considering that you DO get a stock and pistol grip with the G&P kit... Even so, 180$ and 240$ is a lot of money considering the gun itself costs 300$... but i will end up buying one of the two, the original stock is way too unwieldy to use in CQB games for me...

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Has anyone used mlemart before? I've never heard of them ever.. 

 

Nope. And i'm positive it's assembled in Hong Kong, so i'm not sure whether it makes sense to buy something that has been built and packed just down the road, then shipped over to the UK, only to buy it, so they can ship it back..... :rolleyes:

Edited by onizuka-gto
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Iv ordered from them before. The parts came directly from HK, I believe they are based there. I got great service from them, some of the items I wanted had been discontinued by ace1arms so he sent me a free magazine. Since then he has badgered them to make some more and they have done. So iv been pretty impressed with them so far.

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Here is a reply from AG on Facebook, regarding what gas the stock kit is designed for.

 

AngryGun Its for the regular green gas. It must better than original marui gas tank because the material use 6061 Aluminium CNC milling and the capacity larger than original at least twice.

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No idea about expansion ratios, or even if they're relevant, but empirically for a given gas reservoir the higher the pressure of the gas used, the fewer shots you get.

 

Interestingly, unless I'm doing chemistry wrong, 144a can't exist. I say 'can't' because the the numbers are a naming system which describe various things about the structure of the molecule, and 144 is impossible. So who knows what's actually in it, I assume Abbey (they're the only ones selling it I think) called it 144 for familiarity's sake, like a logical/numerical progression from 134.

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No idea about expansion ratios, or even if they're relevant, but empirically for a given gas reservoir the higher the pressure of the gas used, the fewer shots you get.

 

I don't think your empirical research is correct... Consider propane (~140psi at 25°C) and CO2 (~900psi at 25°C). Expansion ratios govern how much gas the liquid you're able to force into the reservoir will expand into. More gas obviously equals more shots. Propane has an expansion ratio of 1:270 (that is, 1cm3 of liquid propane = 270cm3 of gaseous propane), whereas CO2 has an expansion ratio of 1:450 (that is, 1cm3 of liquid CO2 = 450cm3 of gaseous CO2). Therefore, you could squeeze substantially (66% more) CO2 than propane into equal reservoirs, which should translate (all other things being equal, which they aren't) to 66% more shots from the CO2 magazine than from the propane one.

Edited by PureSilver
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I think that's if you make the assumption that an equal amount of liquid is let out every time the trigger is pulled / hammer is dropped regardless of propellant (or more effective yet, equivalent volume of liquid is let out to produce a required volume of gas to propel BBs), but with this being airsoft, nothing is this precise, and usually the valve timer is either controlled by something basic like hammer strike on a valve that re-closes with the pressure of its gas + spring, or by how the weapon cycles and deactivates the valve knocker, essentially, the amount of time the valve is opened in a given system is a constant, so if that's the case, the higher the pressure, the more gas forces its way out of the reservoir, giving a total end result of less total shots.  

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I don't think your empirical research is correct... Consider propane (~140psi at 25°C) and CO2 (~900psi at 25°C). Expansion ratios govern how much gas the liquid you're able to force into the reservoir will expand into. More gas obviously equals more shots. Propane has an expansion ratio of 1:270 (that is, 1cm3 of liquid propane = 270cm3 of gaseous propane), whereas CO2 has an expansion ratio of 1:450 (that is, 1cm3 of liquid CO2 = 450cm3 of gaseous CO2). Therefore, you could squeeze substantially (66% more) CO2 than propane into equal reservoirs, which should translate (all other things being equal, which they aren't) to 66% more shots from the CO2 magazine than from the propane one.

 

It may not be 'correct', but as you say it's empirical and correct based on what I've observed. I wasn't thinking of CO2 when I wrote that post either. No idea about CO2 really, seeing as we can't (or shouldn't anyway ha) charge normal mags with it.

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I think that's if you make the assumption that an equal amount of liquid is let out every time the trigger is pulled

 

Like I said, not all things are equal. Airsoft guns that shoot CO2 tend to have very strong springs and the like, which lessens their gas efficiency. Airsoft guns that shoot CO2 also tend to experience a power bump when doing so, which means they're not equivalent to the propane-powered shots any more. Some gases (although I don't know specifics for CO2 or propane) might suffer from adiabatic cooling more severely than others (causing a more severe or more sustained drop in pressure) which would also affect the amount of gas that escaped. There's a lot of variables that affect how many shots you get out of a gun; my point is that there is no hard-and-fast - or even general - rule that you should get more shots out of a low-pressure gas than a high-pressure one.

 

It may not be 'correct', but as you say it's empirical and correct based on what I've observed.

 

The biggest problem with all this conjecture is we still don't know what's in most airsoft propellants. CO2, propane, dichlorodifluoromethane (R12), chlorodifluoromethane (R22) or 1,1,1,2 tetrafluoroethane (R134a) are one thing, but blended mixes with propane and propene, or as-yet-unidentified replacements for any of the R-numbered chemicals are much harder to identify. If we don't know the chemical characteristics of what we're working with, it's almost impossible to determine how to optimise our guns. Imagine trying to tune a car engine without knowing the octane number of the liquid you're fuelling it with; it could be heavy fuel oil or it could be ether, or anything in between - and the difference between those two relatively similar molecules is enormous.

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I've the opportunity to pick up one of these boomsticks second hand for a good price, could you lads help a brotha out and tell me if:

 

A. Can this take GG without destroying itself in an Irish (moderate) climate and

 

B. What are the major weak points/failings of the system?

 

I've heard the nozzles tend to break and jam, barrel wobbles etc.

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