If you do a forum search on 223 loads in FTR, you'll find lots of threads and hundreds of posts on this subject, chambers, freebore, components and loads. You'll find 80gn class bullets at ~3,000 fps is fairly tame and there are many posts on running 90gn VLDs at 2,850 to 2,900 fps, sometimes 2,900 fps +.
23 grains of Varget, 80 SMK, OAL 2.465" (0.020" ish from lands), 2850 fps in 30" barrel. Brass lasts a long, long time. This load has won a lot of local matches.