why GBB Rifles not common?
 

Can I just ask why is the GBB only available in Pistol or Machine pistol? I've seen some GBB on M16, Ak but never heard in this forum is there a reason behind it?

In my opinion, we do GBB in pistols because of two reasons:

- You cannot fit a battery, motor, etc in a pistol that is game-able.
- GBB makes a realistic looking shot

For rifles, there is no reason to do GBB because there is lots of room to fit batteries and motors. I find GBB a pain in the ass. AEG is safe, no risk, and can fire many rounds in a short amount of time. Swap batteries and keep going.

If you WERE to store a large amount of gas in a rifle, it would then probably become a fire hazard too. (GBB gas is flammable (green gas))

using 134a gas should be safe

If you want a gbb rifle look at classic airsoft. Before AEGs there was gas guns. Some are extremely hard to find and its expensive.

gas at low temp (eg outdoor late fall/winter) condenses and your fps drops dramatically, but you already know this because you love your Chemistry class right?

If someone could fit a drozds into a g36 frame and make it shoot 6mm bb's under 400 that would be a beast of a gun :) . http://www.airgundepot.com/drozdreview.html

GBB rifles aren't common because they are expensive and can ONLY run off an external air system. Some older classics like JAC and MGC operate on a BV (non-moving) air system which allows them to utilize internal tanks.

However, Escorts and SPs can only be run off an external source. There is no way you can make a GBB rifle skirmish able without this. Danger isn't really a problem, as long as the pressure is regulated the gun wont blow up or shoot hot. Green gas typically isn't used in gas air rifles either, from an external source you would usually be using co2 or High Pressure Air (HPA).

Granted SP makes some VERY nice/realistic guns that have the nice sound and recoil, in stock form have about the same range and accuracy as a stock AEG. It also takes a bit of money to get them to compete against upgraded AEGs.

That's not entirely true. There are "Classic Rifles" (such as the Marushin M2 Carbine) that use gas blow back, and do so effectively, without an external system. These are about the only rifles that are common on the field and they shoot with fairly good power (and pack a punch with a 8mm bb) and accuracy. However, their mag limitations make them almost unusable (16 bb's and full auto capability in the M2? that's just silly).

Ah, forgot about those >.<. Also forgot that certain Kokusai, JAC and MGC guns had partial blowback.

If you want a bottle hooked up to your gun, get a paintball marker. And mags that store gas in them are really expensive.
There is a drop in GBB mechbox for AEGs, but now you need to reload gas and mags because it doesnt store alot of gas. What they should do is make a gas chamber that fits in a full stock.
And CO2 would be the only really acceptable gas for that use since it's more stable year round.

i'm not good with chemistry...but its something to with the expansion of gas wtih the pressure drop.

basically in airsoft terms: cool down effect. your gun's ROF will decrease, you will feel the magazine get really cold, your fps will decrease drastically, gas is escaping from within the gun, your gun may lock up and jam in colder weather.

Or in the case of my HFC beretta, the slide only blows back half way.

I think you mean HPA. From past experence with paintball (omg I said paintball!!) CO2 sucks balls during cold weather.

Fuck yea I'd take external powered gas guns over AEGs anyday. Nothing replaces (semi) realistic noise and recoil.

cold weather -20 or cold weather +5?

You can use hpa in any weather really. There are a few classic users around. I have over $2000 in my two classic guns I have. There not cheap in Canada at all.

Simple reason - too many people would get confuzed to kingdom come if they need to reload a mag, or reload their air. :)