My 90 VLD load COAL is 2.636" with the bullets seated at ~.015" off the lands. This is in a .223 Rem chamber cut with a reamer set up for the 90s with .169" freebore. An even longer freebore (.200" or more) would probably be better, as the 90s are seated with the boattail only very slightly above the neck/shoulder junction in my chamber. If the 77s are touching at 2.450", they would be jumping close to .200" in a chamber optimized for the 90s. It is possible that might work reasonably well, but it's also possible it might not. Shortening the freebore to accomodate the shorter bullet is guaranteed to give you problem with the 90s, as a lot of bearing surface is going to be below the bottom of the neck, which is not desirable. If you want to shoot the 90 gr bullets in .223, you're much better off getting a chamber specifically set up for them and hope the 77s/75s will shoot well also. Going the other direction as a compromise for the shorter bullets is not likely to be an approach that will work well for the longer bullets.
Alternatively, the Berger 80.5 fullbore is a great bullet and has the shortest base-to-ogive dimension of the Berger 80-something offerings. It shouldn't be too difficult to have a chamber cut to shoot both 77s and one of the 80-somethings like the 80.5 optimally. Another popular choice would be the Hornady 80 gr Amax. Based on the base-to-ogive measurements of the 77 SMK and the 80 gr bullets, a chambered for the 80s should still allow you to seat the 77s at a reasonable depth relative to the lands. Unfortunately, the 90s are just too long to have a compromise chamber cut. You pretty much want to have it cut for the longest bullet you intend to load.
As far as accuracy, I have found the 80.5s and 90 VLDs to shoot with very good precision. I routinely shoot the 80.5s in 300 yd F-Class matches, and the 90s at 600 and 1000 yd. They shoot more than well enough to be competitive. Performance-wise, the 80.5s start to fall behind a typical .308 shooting 185s past about 300 yd in windy conditions. At 600 yd, the typical 80 gr .223 load will experience more wind drift than even a .308 shooting only 155s. You certainly can shoot 80s at that distance, the potential for precision/accuracy is definitely there, and many have done it successfully. But you'll be giving up more and more to .308s as the distance increases. On the other hand, the 90s will keep up with most .308s shooting 185s (or less) out to 1000 yd. But shooting the 90s comes along with a necessity for very careful and meticulous reloading practices, along with a rifle setup that may be very limited as to what you can shoot out of it.
If you're fairly certain your upper range limit in the near future is 200 yd, I'd have the rifle throated for the 80s, which will probably also be fine for the 77s. Unless you're routinely shooting well past 300 yd, you won't be giving up much, if anything, shooting those. In addition, the 90s won't really be that much additional benefit unless it's typically very windy where you shoot.
