Why do gas blow back mags go cold ?

[pureairsoft11]

As it says in the title, nearly froze my hand off today on mine.

[V.A.K]

Re: Why do gas blow back mags go cold ?

As it says in the title, nearly froze my hand off today on mine.

oh dear god what have you done

[Ajhayter]

Re: Why do gas blow back mags go cold ?

Here, try this:
http://goo.gl/xS8OL


Long story short, as you use gas, the remaining gas in the mag expands. This expansion results in a drop in pressure, which makes the gas cool down.
Fridges work on the same principle. The science is called "boyles law" if you are interested.

[Jez Armstrong]

Obviously never paid attention in chemistry

[Robin-Hood]

Re: Why do gas blow back mags go cold ?

It's basic physics.

Pi * Vi / Ti = Pf * Vf / Tf

Pi = Initial Pressure
Vi = Initial Volume
Ti = Initial Temperature
Pf = Final Pressure
Vf = Final Volume
Tf = Final Temperature

If one of those changes then the others must also change in accordance with this formula. So as the pressure drops. So in a gas mag, the pressure drops, the volume is constant because the size of the mag isn't changing so therefore the temperature must drop.

Blatantly Stolen Examples from the Interweb:

Case 1: A cylinder contain a gas of volume 30 L, at a pressure of 110 kPa and a temperature of 420 K. Find the temperature of the gas which has a volume 40 L at a pressure of 120 kPa.
Vi = 30 L, Pi = 110 kPa, Ti = 420 K, Vf = 40 L, Pf = 120 kPa
Step 1: Substitute the values in the below final temperature equation:
Final Temperature(Tf) = PfVfTi / PiVi
= (120 x 40 x 420) / (110 x 30)
= 2016000 / 3300
Final Temperature(Tf) = 610.91 K
This example will guide you to calculate the final temperature manually.

Case 2: A cylinder contain a gas of volume 10 L, at a pressure of 80 kPa and a temperature of 200 K. Find the temperature of the gas which has a volume 20 L at a temperature of 220 K.
Vi = 10 L, Pi = 80 kPa, Ti = 200 K, Vf = 20 L, Tf = 220 kPa
Step 1: Substitute the values in the below pressure equation:
Final Pressure(Pf) = PiViTf / TiVf
= (80 x 10 x 220) / (200 x 20)
= 176000 / 4000
Final Pressure(Vf) = 44 kPa

[pureairsoft11]

Re: Why do gas blow back mags go cold ?

Here, try this:
http://goo.gl/xS8OL


Long story short, as you use gas, the remaining gas in the mag expands. This expansion results in a drop in pressure, which makes the gas cool down.
Fridges work on the same principle. The science is called "boyles law" if you are interested.

Thankyou mate, i was just curious

[pureairsoft11]

Re: Why do gas blow back mags go cold ?

Obviously never paid attention in chemistry

haha nah i didnt take chemistry i had a choice of chemistry or physics and i took physics

[SAS Scott]

Re: Why do gas blow back mags go cold ?

You got to be shitting me pureairsoft -_-.
Three words.. Cool Down Affect .

[Robin-Hood]

Re: Why do gas blow back mags go cold ?

haha nah i didnt take chemistry i had a choice of chemistry or physics and i took physics

It's covered in physics too haha.
I got taught it in like standard grade iirc.

[Ajhayter]

Re: Why do gas blow back mags go cold ?

If you are looking to avoid it, the only way is to lower your rate of fire. Cooldown really kicks in HARD if you use auto. Obviously the effect is worse in the Winter, when the mags are already at a cold ambient temperature.

M4 mags are quite compact, so you will always have some cool down problems.

G36 Mags are HUGE and as such have a chambered gas reservoir. This reduces the pressure drop and helps reduce cooldown.

[V.A.K]

Re: Why do gas blow back mags go cold ?

Obviously never paid attention in chemistry

and you didn't listen in physics

[pureairsoft11]

Re: Why do gas blow back mags go cold ?

Im sure i havent been teached that :P

[Jez Armstrong]

and you didn't listen in physics

Explain

[Robin-Hood]

Re: Why do gas blow back mags go cold ?

Explain

For the third time, gas laws are taught in Physics as well.

[V.A.K]

Re: Why do gas blow back mags go cold ?

Im sure i havent been teached that :P

You haven't been taught english by the looks of it, I think don't quote me on this it's taught in year 10 I learnt it many moons ago when i did my gcses