As I was gutting him it looks like ALL of the accubonds buzzed right through like a full metal jacket doing no damage.
That's unreal, and obviously a batch of defective bullets. No one is so unlucky as to experience 0 for 5 - no expansion. I consider non-expansion to be the most disgusting mode of bullet failure possible, in an expanding hunting bullet. I've experienced it with Nosler Ballistic tips, as well as Berger VLDs. You can prep everything properly, set up and execute properly, and still be instantly thrown into a three ring circus if a bullet pencils thru the ribs. I've not been lucky enough to have them tumble. Caliber hole entrance. Caliber hole exit. Just like shooting an arrow thru the animal with a field tip.
Never yet experienced failure to expand with an Accubond. In fact I've had good performance from every Accubond I've killed game with so far - in both .284 and .308 caliber bullets. Haven't used them for a number of years now, but not because they didn't perform/expand. How old were these 225gr Accubonds? I purchased a box of 50 maybe 8-10 years ago, and the stems on the white plastic tips deteriorated on some of them, to the point they fell out of the bullets. I found white plastic tips and small crumbles of white plastic in the box, solely from sitting on the shelf in my reloading room. Nosler said they had a problem with corrosion/deterioration of their plastic tips for a short period of time before correcting that problem. They sent me a new box of 250gr Accubonds at my request, to replace the faulty box of bullets in my possession.
Other than shooting thru an animal with no expansion, another concern is a bullet that expands so quickly that the vitals aren't reached on a large game animal. Particularly if the animal has large teeth, claws, and/or hooves and is charging at close range. Never had a complete blowup yet. Likely won't, as I shoot into the ribs - broadside profile when possible - so it doesn't take much bullet structure to reach the vitals.
Glad you recovered your elk.