I've got a Remington 600 in 308 with an 18 inch barrel that is a real tackdriver and a joy to carry afield.Browning made a BLR in 308,probably still do.If I'm not mistaken Remington made both pumps and autos in 308 with an 18 inch barrel.At those kind of ranges 6 inches of barrel and the lost velocity are a moot point.It will still be moving faster than a 30-30.
Howard

My .308 is a Rem 7 with a 20 inch barrel. It is an old orginal 18.5 inch barrel that I rebarreled.

I like the 20 better but the 18 inch was good. I often shoot the 20 inch barrel at long ranges and it works just fine. The wind is the big deal at long range, and another 2 or even 4 inches ain't going to do squat.

Anyone here have the Ruger Intl? How do you like it?

I've owned a Ruger 77RL (ultra light) rifle, which has a 20" barrel, in .308. Killed several deer with it and it works real well. We do some deer drives around here in the thick stuff. My personal opinion is that I wouldn't go any shorter than about 20" as that is ideal, any shorter and muzzle blast is ferocious. Since I've killed deer at up to 250 yards with the ultra light, it pretty much is good for any kind of hunting. I'm really not interested in going any shorter. I feel, at least for me, that the Ruger compacts are too small.