About 12 years ago I shot a really nice mule deer buck at about 550 yards with my 338 win mag loaded with 225 barnes x bullets. I hit the deer perfect behind the shoulder and it took off. I hit it again and the deer disappeared. I looked for the deer all day long and finally saw it walking about 1000 yards away. It vanished and I couldn't find it. The next day when I had almost given up, I found the deer. Both bullets had pencilled the buck. No expansion and no wound channel. I don't know the cause of this, but the bullets didn't expand. I killed another deer at about 300 yards and it never took a step, but the bullet hit bone in the neck. I had one other kill with the barnes x that baffled me and it was a doe that I shot in the head, looking straight at me at about 150 yards killed her dead, but the bullet didn't exit.
On the plus side, I killed several elk one year with 210 gr xlc barnes bullets shot out of my 338 rum. Both were one shot kills, one at 200 yards, and the other was a finishing shot on a cow that my brother had hit in the ham with a 7 mag, at about 550 yards that broke both shoulders dropping her on the spot. I recovered the bullet on that shot and 3 petals were intact, perfect mushroom and it was in the far shoulder.
The main reason I stopped shooting the x bullet was that my factory barrel on my 338 rum went bad and the new douglas didn't like the barnes or a lot of other bullets. We will see how my new broughton barrel likes the 225 tts later this week.