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LM4 PTR - Heated Magazines

LM4 magazine heated winter

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#1 General Pickle

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Posted 05 November 2013 - 12:11 AM

Hello KWA users. I had a discussion with a classmate today and discovered an interesting piece of technology which I thought I might share with you.

Winter is coming very quickly, and that means that many LM4 users will be unable to train or play airsoft for the next few months. Those of us who were fortunate enough to purchase an RM4 are in luck, however some of us must suffer with no chance of obtaining a recoiling airsoft gun for the Winter.

What is it that keeps us from using the LM4 during the winter? Well, the basic problem is that the gas inside the magazine is in a compressed state, so when we fire the replica we cause the magazine gas chamber to rapidly decompress for a short time. This rapid decompression of the magazine causes a temperature drop, which in turn causes the remaining gases in the magazine to contract and lose overall system pressure. We know if a magazine is warm that it will perform far better than if it were cold, so we need to find a way to make the magazines warm even when faced with low temperatures.

I've heard many people, whether it be online or in person, toy with the idea of putting skiing hand warmers around their magazines in an effort to warm the gases. The problem with this method is that we have no way to control the amount of heat being transferred to the magazines, thus we warm the gases too much and cause inconsistent velocities. All in all, this solution is not exactly scientific.

By using thermoelectric cooling modules, this idea may actually be possible. Forgive me if I leave out some details, as I am certainly not an expert on TEC technologies, but the general explanation I got was that these are small and flat electronically controlled modules which are cold on one side, warm on the other side. Generally these units are under 5mm thick and can be sized in various ways. The maximum voltage tends to be only a couple volts, so a watch battery might even be a viable power solution. Essentially the idea would be to create an external shell for an LM4 magazine which can precisely control the temperature of the gases, regardless of external conditions. Unfortunately these units are fairly expensive, but I think there are a few of us crazy people who may be willing to throw a little extra money at the LM4 if it were to perform normally at freezing temperatures.

What do you think? Is it plausible? Is it too radical and complex? Is this exactly the idea we need?

#2 Chuck S

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Posted 05 November 2013 - 03:56 AM

If you come up with something please keep us informed.  LM4 magazine capacity is under 40 rounds so we're at at a disadvantage to start.

Technology aside if the magazines are kept under the jacket, as close to the skin as possible they will stay warm.  Will require swapping magazines frequently but it's a proven method.  The plastic body Magpuls will probably retain heat longer than the metal shell GI type.  Same with the green gas canisters.  Don't leave either in your car overnight or it will take quite a while to get them to room -- er, body -- temperature.

-- Chuck

#3 General Pickle

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Posted 05 November 2013 - 11:30 AM

View PostChuck S, on 05 November 2013 - 03:56 AM, said:

If you come up with something please keep us informed.  LM4 magazine capacity is under 40 rounds so we're at at a disadvantage to start.

Technology aside if the magazines are kept under the jacket, as close to the skin as possible they will stay warm.  Will require swapping magazines frequently but it's a proven method.  The plastic body Magpuls will probably retain heat longer than the metal shell GI type.  Same with the green gas canisters.  Don't leave either in your car overnight or it will take quite a while to get them to room -- er, body -- temperature.

-- Chuck

For sure, I've been making use of the 'arm pit' method for a while now, but of course the problem comes when we put the magazine in the gun or when we need another magazine. Perhaps using a 'Surefire' fat mag style shell would allow for more space to work with, more battery capacity, larger TEC units, more precise control instruments etc. Perhaps this falls into the realm of classified KWA intel, but have any of KWA's engineers considered this type of technology? Obviously it would increase the price of magazines significantly, but in the world where money is no object, has there been testing or even calculations as to how something like this could work?

I will likely add this to my little independent project list, for when I have more time and money to throw at a single magazine :P

#4 BeachEMT

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Posted 05 November 2013 - 01:27 PM

You don't even need a TEC. All you need is a battery, resistor and a switch if you want to be able to turn it on or off. TECs are used as cold plates. Since you just need the hot side, resistors are cheaper, smaller and simpler.

#5 General Pickle

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Posted 05 November 2013 - 02:03 PM

Resistors may well be a more efficient option, especially when talking about cost. I found that the TEC's were rather attractive given their large surface area by nature, perhaps lending themselves to very even heat distribution to the magazine. After a quick internet search, it seems that flat resistors with large surface area are not as uncommon as I thought originally. Typically when I think of resistors the first image that comes to mind is an axial-lead resistor.

Thanks for the catch, Beach, this could be a much cheaper and more reasonable solution.





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