Generally speaking, not much. But when you're dealing with scenario games in paintball, the types of markers (the favored term for all paintball guns) can vary.
The thing is, woodsball (paintball games that center more around scenarios and mil-sim) takes a lot from real-world military tactics. In the real world, machine guns are used to achieve superiority in firepower. But because firing rapidly causes a lot of wear on the gun itself and also makes it prone to overheating, machine guns have to be built heavier to withstand the wear.
Having said that, you can say that a paintball marker that is built or modified for rapid-fire capabilities is a paint machine gun. If that is what you're planning to get, I recommend a Tippmann A-5 with upgraded internals (to better deal with the rapid fire) and either a response trigger or electronic trigger. Put an M249 buttstock and shroud kit along with a longer barrel and bipod, and you have a pretty good representation of a SAW (Squad Automatic Weapon).
A sub-machine gun fires pistol cartridges. A machine gun fires rifle rounds.
There is no difference between an AR rifle and an AR rifle
A sporter air rifle and what?
About .05, obviously.
There is no difference.
A carbine is a type of rifle.
Nothing
The M4 is capable of automatic fire, the AR 15 is not
.22 Long Rifle is a longer cartridge.
A musket is smooth bored, like a shotgun's bore. A rifle has rifling inside the bore (grooves).
Deff a sniper rifle
Take a sturdy folder and make random holes and angles in it, take the colors you and to paint the rifle with and paint it.