Gonna be pretty hard to beat the Ruger SFAR in terms of lightweight for an autoloader .308 and since it's an AR it will likely be accurate. Under $1000 and all you'll need is an optic and a trigger for a few hundred more.
I find the factory SFAR trigger to be decent out of the box. But, since you can drop any aftermarket AR trigger in it, the sky’s the limit. I’m a bang for buck kinda guy and the SFAR has that in spades.