try numerich or brownells Brownells has a good selection. Try http://www.brownells.com/
You should really leave this to a gunsmith.
The longest barrel that isn't ridiculous is 22 inch. It is a Carbon fiber barrel made by Paintball Assassins
The barrel is just a tube, there is nothing "in" it. If you are asking what it is made out of, most of them are aluminum, there are a few ceramic and carbon fiber ones as well though.
If you need better accuracy, buy a Custom products 2 piece barrel. If you need better range, buy an Apex tipped barrel. If you need a lighter barrel, buy a Carbon fiber barrel, like the Azodin Carbon or Stifi MF.
A CP onepiece aluminum barrel 10-14 inches is a very good all around barrel. If yo have the money, go for a carbon fiber barrel. If you play on playing woodsball, you should look into an APEX tip.
well, since I own and shoot one- yes, they can be made. The barrel is steel, the frame of the gun is carbon fiber. Mine is a Bushmaster CARbon 15.
Yes, fiber is a carbohydrate and is extremely important to your diet. It is what is known as a complex carbohydrate. That is why it is placed on the nutrition label under the carbohydrates. It is essential to eat foods high in fiber and low in sugars (simple carbohydrates). By the way, if you were to search, "is fiber a carbohydrate," you will find many web sights confirming this fact.
barrel and action is steel, The other parts can be wood or some type of fiber. Comsosite plastic, fiberglass is the make up on some.
id go Freak jr. you have the sizing options that will help with accuracy and efficiency, the MF isn't all that great IMO, you run more of a risk of damaging the threads by not having them be metal. also look into the deadly wind fibur (yes that's how it is spelled) it is a carbon fiber barrel that uses the freak inserts, so you basically have a carbon fiber freak barrel, and it is amazing (i own one) it basically feels like playing without a barrel on your marker
Fiber
B-fiber are DULL PAIN!
a natural fiber