Re: Thoughts on barrel length
The reasons guys want push 155gr rounds to 2950fps is, that is what the F Class F/TR are looking to do. Basically it's a way to make a 308 perform like a 260. When all else is equal, like in F Class or Palma, the faster you can push the rounds the better off you'll be.
However, tactically speaking a lighter accurate rifle that allows the user to maneuver is going to trump the need for speed with a longer barreled rifle. You can't underestimate the benefits of a short handy rifle.
I shoot 155gr Scenars out of my Gladius all the time. (18.5" - 1/10) and it performs very well. During one of the SH Online Training lessons regarding the wind I shot paper around 600 yards several different 308 rounds out of the 18" Gladius and noted the down range results... and I find the 155gr Scenars do very well.
When choosing any LR 308 really you want to consider the 155gr or the 175gr in factory offerings. You can handload to better results but definitely not with a 168gr round, it's not a good LR round especially for windy conditions.
Others options are available, you can look at the new 178gr Superformance, although we have been seeing pressure issues on summer days, or the 170gr HPS... the 22" Harbinger during the 600 yard group shot beat even the wind cheaters... held a Mil of wind and fired a 3.25" - 5 shot group for score winning that segment. the HPS runs fast and has a BC of .525, but doesn't perform in every rifle.
Bottom line, pick the right combination for the situation, if you're gonna shoot competitions and carry your rifle from the car to the line and back, have at it, go long, push hard, do whatever you need to in order to get the edge. If you 're going tactical, go shorter, and be smart about it. if you're going short and then talking about 1000 yards shooting everyday, well you choose wrong. In that case, consider a short wind cheater...smaller faster bullet. You can push a 260 out of an 18" barrel better than you can push a 155gr out of a 26" -- too all things there is a trade off.
Do your home work and think about it, but understand I would rather carry the Gladius and be light and accurate inside 800, than to lug around some 32" monstrosity thinking it will make a difference at 1000 yards... cause it won't unless you get sighters, time to rest, etc. Tactically speaking light is right