Namely, the J36 120gr bullets, with a supposed .687 BC. They have a copper tip over an open cavity in the nose for expansion, and are very long for their caliber, hence the high BC numbers. I haven't run them in my 6.5-06 yet, because I'm having so much fun with the Lapua bullets, and also because those 20 Lost River bullets cost me nearly $20.00 with shipping and handling. They look wicked and well-made, but from what I gather from my fellow F-Class shooters, are hard to get shooting well.
I also had a box of J40 144gr target bullets I sent a friend to try in his 6.5x55 Howa sporter. Before I shipped them, I took a look at them - they looked like they had been turned individually on a lathe, and rather roughly at that. Again, these are expensive bullets to have essentially machine threads still appearing on their jackets.
From left to right, a selection of 6.5mm bullets from my reloading bench, starting with a Sierra 120gr MatchKing, a Nosler 120gr Ballistic Tip, a Lapua 123gr Scenar, a Lost River 120gr J36, and a Lost River 132gr J40:
As for FMJ and HPBTM bullets not expanding, they probably would, were one to hit bone or construction materials. However, the military FMJ ammo is specifically designed to stay more or less together per the Hague Conventions, and target bullets like the Sierra MatchKings owe their design strictly to generating best accuracy while making nice holes in thin paper and cardboard targets. The hollow point of a Hollow Point Boat Tail Match bullet is strictly an after-effect of the jacket drawing process, don't read any purpose into other than that. If you use one for hunting edible game, you're on your own.
Pelt hunters actually like non-expanding bullets, so they use either military FMJ or Sierra MatchKings to minimize the size of the holes they drill into their quarry. There are many hunters, especially on the Internet forums like TFL and THR, who brag about how they deer hunt with MatchKings and military ball ammo, stating that they do nothing but head shots with minute-of-deer-eyebulb shooting afield. Of course, everybody on the 'Net shoots benchrest accuracy unsupported and offhand during deer season, so it should really come as no surprise that they would prefer that type of projectile vs. something designed to actually expand and humanely take game.
Likewise, select a hunting bullet based on what you want to hunt. I've tried the Nosler 120gr Ballistic Tip on both armadillo and whitetail, leaving my 6.5-06 at an honest 3200fps. When struck in the brown eye, the majority of the armadillo vaporized in a pink mist, leaving basically a rocking shell on the ground. (Say what you will about the last thing going through his mind...) The whitetail had a horrible amount of ruined (liquified) meat, and was literally sprinkled through the wound channel with tiny little flecks of copper. I'd call it dramatically effective, and not particularly what I was looking for in an edible game bullet. I understand that Nosler has since then redesigned the bullet, but to me it will probably never be more than a varmint bullet.