There are non refillable, disposable cartridges that range from the standard 12 grams to 4 oz. There are also small refillable 45 butt stock tanks and other small and long tanks like it. After 4 oz, a tank must be fitted with a "burst disk" which allows it to bleed out if over pressurized.
Any refillable tank over 2 inches in diameter needs to be hydro-tested every five years.
Many of the retail sporting goods stores will have refill stations for your cylinders. Also, I have seen hardware stores that will do that too. Where did you buy the gun? Chances are that the store the gun was purchased from will be able to refill the cylinder for you.
At a paintball or sporting goods store.
Take it to a shop! if you want to do it yourself the normal way is to put the bottle on scales and fill it from a larger bottle to a fill weight. To be honest though CO2 is well out of date. A smart move would be to move onto compressed air.
Call them and ask!
No, you must have it refilled at a paintball field or pro-shop. You cannot refill paintball tanks from low pressure Soda dispenser C02 tanks.
T-Square Paintball, Jacksonville Arkansas
No, but Dicks sporting goods does.
Usually specialized paintball "pro shops" that sell paintball markers, paint[balls] in quantities of 2000 or so, paintball gear (apparel, safety googles air tanks), and may offer refills for air tanks. Usually there will be one within a paintball field or pretty close to one, and some may may be miles away from the nearest field.
Paintball guns can use Co2 from any company, they are all built the same. You can find valved tanks and 12 gram's at sporting stores, paintball fields and proshops.
Almost all paintball fields have them, and some sporting goods stores. But also check diving shops, gas shops (places that sell oxygen and co2 tanks) and firehouses, if they are closer.
Carbon dioxide can be prepared for air guns by using pre-filled CO2 cartridges or tanks that are specifically designed for this purpose. These cartridges or tanks can be purchased at sporting goods stores or online. It is important to follow manufacturer instructions for safely loading and using CO2 in air guns.
In a perfectly mathmatic world: 4. Realistically 2 and a half just from leaked air and lack of pressure after fills.