I've shot the 140amax, 140 Berger hybrids, 142smk, 139 scenars, 120amax, and 140 Berger VLD target and hunting bullets as well as factory loads from my 6.5 Creedmoor. Here's my opinion.
Factory 140amax will give you match accuracy up to 1000 yards. Don't waste your time with lighter bullets unless you are shooting short distances only, less than 600 yds or have a semi-auto that can't handle the heavies, it makes a bigger difference at longer distances and I haven't been able to push the lighter bullets fast enough to make up for lower BC.
I like the 142smk and 140gr Bergers better than the Scenars because I point my bullets, that is just me.
The VLDs are very sensitive to seating length dependent which can effect accuracy at shorter distances (50-100yds) but at longer distances my groups have tightened up and their high BC beat almost anything else out there for wind drift which is what matters the most at 1000 yards on beyond. Just work and the seating length as quoted from Berger website:
"For years we have relayed that it is best to jam the VLD into the lands for best performance. This works for many rifles however there are many rifles that do not shoot the VLD well when the bullet is jammed. We have learned that the VLD can shoot best as much as .150 jump off the rifling. VLD bullets can be sensitive to seating depth and it has been found that these bullets shoot best in a COAL “sweet spot”. This sweet spot is a COAL range that is usually .030 to .040 wide.
The quickest way to find this sweet spot is to load ammo at four different COAL. Start with a COAL that allows the bullet to touch the rifling. The next COAL needs to be .040 off the lands. The third COAL needs to be .080 off the lands. The last COAL needs to be .120 off the lands. One of these COAL will outperform the other three by a considerable margin. It has been reported that the VLD bullets don’t group as well at 100 yards but get better as the bullet “goes to sleep” at further ranges. We have learned that by doing the four COAL test you will find a COAL where the VLD bullets will group well at 100 yards. Once the COAL that shoots best is established you can tweak +/- .005 or .010 to increase precision or you can adjust powder charges and other load variables. Frankly, those who do the four COAL test usually are happy with the results they get from this test alone."
The hybrids are less sensitive to seating length and what I like to use with the 142smk as close second for anything pass 800 yards.