I don't use them but everything I've read say's that the X bullet builds more pressure due to the lack of groves in the bullet. The TSX has the groves and pressure is reduced and copper fouling is greatly reduced. As I understand the only difference is the groves. Looked at a Barnes catalog yesterday and think if I were going to use them, I'd go with the new tipped TSX. I do believe that it will make expansion more reliable. Winchester went to it on their bullet like that and that is one of the reasons they claim they did it. Have read a few reports of the TSX shooting thru without opening.

I use the TSX in my 300 rum reloads and love the results... excellent accuracy and astounding on game. I used to use the X on my 308 but I think I like the accuracy better with the TSX. I have not done a side by side comparison though.

When I get the 6.8 Rem SPC barrel for my Encore I am going to try the TTSX.

I haven't used the Barnes X bullets on game, but, as I posted in the Hornady Solids? thread in the African forum, I've used both 270 gr and 300 gr Barnes TSX bullets in my .375 Rem Ultra Mag on 2 hunts in Africa. I've taken 18 animals with this combination, ranging from size of Steenbok to Cape Buffalo, and other than being too much gun for the smaller animals, the TSX bullets worked perfectly.

I am currently putting together a .300 Weatherby Vanguard, and the bullet that I hope to use in it is the Barnes 180 gr TSX. This will be my Elk, Moose, and large African antelope rifle.

The 500gr. TSX caught my eye early last fall. Loaded up a smokeless load for the 45-70 that shows 1550 fps. on the chrony with that bullet.
They shoot real nice out of the Sharps and my intentions were to try it out last deer season but took the 45-60 levergun out instead. Maybe next season I'll put them to use.