Re: LR308 build
Yah, I don't think the OP knows what a LR308 is. The LR308 is specific rifle, it's an AR10 style rifle by DPMS. There are a couple different submodels, but no one else makes the "LR308".
Since you ask about different barrel manufacturers, you're not building an LR308, you're building an AR10-type platform. It's a general design category that several companies make guns/parts for. Certain AR10 things may work for you, others will not.
So if you want more replies, ask about .308 AR10s in general.
If you went and bought a LR-308 lower, then you need to first decide on a compatible upper, then a compatible barrel mounting system, and finally a barrel.
A barrel for an LR-308 lower with no intended purpose is pretty vague and unlikely to get forum responses.
What are your intended targets/distances for shooting? 100 yds, 800 yds, I don't know I play video games and like 308 I think...
What ammo are you going to be using? Milsurp 147gr, Match grade 175gr, solid brass hunting handloads, etc.
What are parts do you want on the gun? Certain piston kits and gas ports are mutually exclusive...
And finally, if you're just asking about the barrel manufacturers themselves, then this has absolutely nothing to do with LR-308 rifles, and this thread should be called "Who's your favorite barrel manufacturer and why?".