Im in exactly the same boat man-wanting something to hunt with and also have a riot with at the range. though Im in Canada so I cant choose the ar10 which is practical, light and optics ready unlike the m1a.
I LOVE 18-20" barrel 308s. So much power in a tiny package- they retain the accuracy(and most of the power) of the cartridge but become far handier/lighter for say hunting/actually using your gun not just putting it on a bipod/bench.
I bought an m1a scout model with the 18" bbl. . I think it comes out to 10lbs scoped but Id have to check. It aint light but its doable....but I second guessed myself not sure if I REALLY want to hunt with it.....It seems more suited to climbing atop a church/local walmart with a crate of ammo to engage the zombie horde from a distance.....
so I bought a remington 700 LTR. Forget the chassis you mentioned if you want a lighter tactical style bolt rifle...well it IS called the light tactical rifle....LTR...HS precision stock(not a throwaway), heavy 20" bbbl and fluted for a total weight of 7.5lbs. Fit the bill for me perfectly as a tactical but not too heavy handy 308