Excellent thread, as always Brad.
I was lucky enough to try out a few 6 lb. class rifles that belonged to JimF if you remember him. It convinced me to not go below 7 3/4's lbs. loaded with a sling.
I didn't realize for many years just how important weight was until I started playing around with a 26 inch barreled, 10.5 lb. .308. Shot two five shot groups one day, once I learned how to read the ever changing wind, at 547 yds. Both groups, five shots each, were shot from a sitting position with a military style shooting sling. Both were 6 inches across.
There are a few things one can do to help a light rifle shoot better from field positions. One is to build the rifle with as long a barrel as you can tolerate. The other, is to use a good shooting sling. At present, my favorites are the 3 pt. Ching Sling and the African Ching Sling which works with only two attachment points. E