Yes, each cartridge only contains a specific amount of CO2 which eventually needs replacing.
Well, the legal FPS for an airsoft gun is 450, but you can get snipers, AEG's, etc. that run up to 600 FPS and beyond.
Yes. If it's an airsoft it will sting. If its a BB gun or pellet gun it can penetrate the skin and do damage to a person.
It is a gas and can be used to propel projectiles.
Only if it is malfunctioning
On certain pistols and rifles, yes. You'd need to see if you can buy C02 mags for the certain gun you have.
An Airsoft gun
It all depends on the gun and what powers it. Pump. Green gas, C02, Spring. Some fire at 150 FPS some fire at 450 FPS. (Feet per second)
A pump airsoft gun is a gun that has to be pumped every time before shooting. Ex. Airsoft shotgun
No
No
It is an airsoft gun based of the PPSH-41 gun
That depends on how much you want to spend. You could spend anything from $12 for a really cheap gun, the middle-ground variety whichis $30-$100, or if your rich you could buy a gun in the $500+ plus range. But so you know there are a lot of $1000+ dollar airsoft guns. I got mine for about 50 dollars and it works perfect. The best place to get an airsoft gun is Dicks. They have some good ones, but it depends on where you live. a good spring gun is 35+. a good Electric or AEG is 60+. a good Sniper is 100+ a good C02 pistol is 50+. a good C02 gun is 100+.