accubonds have been one of the most reliable bullets I've been around, until two days ago when my 10 year old son shot his first deer. It was a 130 out of a .260, 200 yards broadside on a decent little whitetail. Shot was perfect behind the shoulder, but the deer ran about 100 and went down, but kept his head up for several minutes, then tried to get up. I set my son up for a second shot, he hit in the heart at 250. The first bullet didn't get into the vitals, entrance hole was the size of a baseball. I've never seen an accubond do this, I've heard they don't always open at long range low velocity impacts, but haven't seen it personally. Nobody is perfect, I'm going to chalk this one up as a fluke until I see it happen again.