From my limited experience....
I have used Barnes bullets for over 15 years. However mostly in smaller calibers like the .243, and 25/06. I loaded many rounds for other folks years back who shot deer and other stuff with them in both the .270 and 30/06, and never got any complaints.
From my experiences and relating theirs, there haven't been much of a trail to follow. Generally whatever was shot just hit the ground. That said, when something did run after being hit, it was dependant on the area hit as to how much blood the critter left. Basically any hit that would leave a good trail did, but just like any other bullet, there are times when the hit isn't perfect, so the trail is just minute. The general distinguishing factor with the Barnes bullets is their ability to penetrate deeper and further than most other expanding bullets.
The "X" bullet and the newer version "Triple Shock", are both expanding bullets in that the nose opens up and peels back into 4 petals. THe resulting wound channel isn't generally as drastic as most lead point bullets which open up quickly then start to funnel down. The X bullet will make a general wound channel all the way through an animal that is about 2.5 - 3" or so wide which delivers the shock over a wider area. Sometimes after hitting heavy bone one or more of the petals will fragment off which will add to the damage. However in about 80 - 90% of the animals I have taken it has just been a thru and thru hole and the animals dropped right there, or within about 50 yds.
Now hopefully your not like this one fellow I loaded for, he wanted a bullet that would drop a deer right where it stood, then came back after hunting telling me those bullets didn't work worth a crap. I was surprised and asked what the problem was, did he lose a deer? No he said, I shot two, both hit the ground not taking another step. I asked and, at what point did the bullets not work like he wanted? He said after he climed down from his perch on the rocks, the grass was about 3' tall and looked totally different from down where the deer were than it did from up top of the ridge, and there was no blood trail to help him locate the deer. Took him about 45 minutes and several trips up the hill to locate them both. LOL
LAter,