I use Barnes X bullets more than any other bullet. I have heard that they are either very accurate or inaccurate but, in all of my tested rifles, they group 1MOA or better. Can't explain why they are finiky, I guess they just are.
The new TSX bullets with their three grooves are supposed to bring more consistent accuracy, but, regardless of which Barnes bullet you shoot, their all copper construction is without doubt the toughest hunting bullet you can shoot. As such, they are, in all honesty, overkill for thin skinned game like whitetails (when compared to Hogs, etc.), so you should use very light for caliber X bullets for whitetails (ie. use 150 grain X bullets in a .30-06 rather than 165s, and 140s in 7mm rather than 160s, etc.)
Zachary