As to the 100 gr BT's and rabbits, I think high velocity and THIN RABBIT skin is subject to this effect re: of bullet construction. I don't think a rabbit is a fair 'test medium' for any rifle ctg. Now a thicker hided animal would tell more I believe.
I TRULY doubt the bullet is disintegrating as would say a 243 with 70 gr TNT. I destroyed a rabbit with a 85 BTHP in a 243 similarly, yet seen it hit a deer and destroy vitals like a larger caliber.
I would not hesitate using a 100 gr, but would prefer more lead, because they hold up better longer, and get it done in 6.5mm