I an looking into buying a California legal 308 firearm for long range target shooting. I have about $2000 to spend. I was originally looking at AR15s with 24" Bull Barrel but was told that if I want to do long range it would be better to go with a 308 like an R 700 or AR10??? This will be my first firearm so I could use some suggestions as to a good entry level setup including scope. I am thinking a used setup might allow me to afford something a little better in quality for my $2000????