I have a question for you. I have a flat-top uper receiver with a 24" bull barrel on it. I've noticed that when I shoot it, what I can best describe as "streaking" occurs where the barrel meets the gas block. I'm pretty sure that it's CLP but where the hell is it coming from and is it safe?

Sounds like you have a small gas leak between your barrel & gas block.

Its not a problem unless your rifle isn't functioning properly.

On all AR-15 gas blocks, you will get a slight leak.  

The barrel gas port is dimensioned with this in mind, and the slight leak should not cause a problem in regards to the cycling function.

Note: If your running a flat top target rig, you are better off with an adjustable gas tube that you can turn the pressure to the carrier down.  This allows you to adjust the pressure to the carrier with just enough pressure to cycle the action, and not have the unneeded pressure lost out the action, instead of pressurizing the bullet and gaining extra bullet speed before it leaves the barrel.