The last time I recovered a 120-grain 6.5mm Ballistic Tip was a decade ago, when I shot one started at 3100 fps just inside the right shoulder of a doe pronghorn almost facing me at about 250 yards. The bullet was recovered under the hide of the left ham, retaining 59.4% of its weight.
Haven't tried the 6.5mm SST on anything, but two years ago went on a whitetail and pig cull/trophy hunt in South Texas with some other folks. We were all using .308 Winchesters, with Fiocchi factory ammo loaded with 150-grain SSTs. The ranges were all inside 150 yards, if I recall correctly, and we didn't recover a single bullet, even on a 200-pound buck shot frontally at an angle, and a 200-pound boar shot through both shoulders and the spine.
In general, I have found Ballistic Tips and SSTs act much like Interlocks of the same approximate weight and diameter these days. When recovered (not many are) they all retain about 50% of their weight, give or take 10%. This is true even when Ballistic Tips lose their cores, because the jacket weighs more than in conventional cup-and-cores.
