Paintball Question: Please help!?

Kingman (Spyder) produces low-end stuff. The marker is fine as a beginner gun if you take good care of it, but the barrel won't be anything special. Get a J&J, CP or Smart parts barrel, they're better quality by far and not overly expensive. 12-14 inches is all the length you need too, shorter or longer tends to hamper performance a little.