Yes they will all "fit" in that they will screw into the standard asa fitting. However not all guns are compatible with both CO2 and HPA. Check the manual before selecting a tanks.
Almost all paintball guns fit standard 5, 9 or 20 oz tanks as well as air tanks.
At any local paintball store.
No, any tank will work.
At some sporting goods stores or any paintball field.
Any gun with a High Pressure System (which is basically all of them) can use this tank.
Dicks, any paintball shop, and Gander Mt.
Yes, you can use any size tank
you need Co2 to fire any paintball gun, it is what physically moves the ball out of the barrel.
No, paintball trigger may not even sit on the same brand. It should list the model the trigger is for.
Where the air tank or co2 tank normally attaches