Mapper - All the information that I have given to you is based on our AR Service rifles that have 1in7.7 Kreiger barrels with Wylde chambers. When I was piercing primers I had a CLE chamber (extra virginal tight) and that might have been part of it. A 1in8 will shoot 77s and 80s just fine. The 77 SMK was designed to be loaded at magazine length for matches like the National Trophy Infantry Team (Rattle Battle) where you start at 600 yards and fire as many rounds as you can get on a target in 50 seconds.
As for the Federals, try them, if your not using super hot loads they may be fine, just start at a reasonable load and work up safely.