This is the internet I all sorts of BS finds it's way under the bridge but REQUIRING a trackin dog is pure silliness.
The thing that jumped out most to me in the first post was the fact he was aiming behind the shoulder. IMO that's where the problem starts. All things are fine and great IF you hit right behind it but miss a couple inches back and you'll be lucky to find the deer. If the deer is even at the slightest cant towards you then even if you hit right behind the shoulder you may be SOL. Had it happen to me this year:
50 yard shot, slightly quartering into me, off hand. Thought I hit low but had a good blood trail so I started trackin. Got over to where a friend was on stand and he opened up as I pushed some other deer outta the thicket. The deer I shot though came right back in front of me, blood all down the side RIGHT BEHIND THE SHOULDER. After some gutting of the other deer I went back to work on the blood trail which had slowed to a trickle. 1/2 mile later I jumped that doe up and off it went. No blood and no hope after that. My shooting and the fact that it was facing slightly towards me caused the lost deer (And no I didn't sit down and have a good cry over it).
Years ago I read the best place to aim on deer was the off side shoulder. Not the one you see, the one you don't. Aiming there it's about impossible to miss the vitals. It's something I always try to do yet as my story indicates isn't always accomplished.
As for the bullet failure or not....... There is not one current commercially available .30-30 round that won't drop a deer if the shooter does his part. Bullet failure my butt.