I opened the crack slightly so it would be more visible in the picture. If you look carefully, you can see the discoloration extending back along the case almost halfway.That's from the escaping gas when the neck failed.
That drop on pressure caused the bullet to hit about 4 inches low. It was at 6 o'clock in the 8 ring. Cost me two points in the slow fire string of the Garand match. Not a big deal, since I only shot an 82 in the off-hand and finished in the middle of the standings.
I carefully inspected the rest of the brass and it all looks fine. They go in the scrap bucket anyway.