From their website:

The new Tipped TSX™ bullet has already been tested in Africa this past May by Dave Scovill –editor of Handloader, Rifle and Successful Hunter magazines.
Dave was the first to try this new bullet out. He used a .300 belted magnum and our 130-grain Tipped TSX bullets. He took impala, warthog, blue wildebeest, kudu and jackals. Dave said the results were unbelievable. He said the internal damage these bullets created was like nothing he had ever seen before. Even the guy who cut up the meat in camp took the time to come to Dave and, in total amazement say, “I don’t know what you shot these animals with! I have never seen the kind of internal damage this bullet caused.”
Dave said the bullet gave explosive results, adding that, “everything inside looked like hamburger, but the bullet still exited the animal.” Dave said it seemed to him that, with both the Tipped TSX and Triple-Shock Bullet, “the faster you shoot these bullets the better they work.”
The Tipped TSX (TTSX™ ) bullet features a polymer tip extending into a specially engineered nose cavity in the all-copper TSX body. The combination of tip and cavity initiates rapid expansion the instant the bullet strikes game. The streamlined tip also increases the ballistic coefficient of the TTSX bullets for superior long-range performance. This bullet expands reliably over a broad range of velocities.
Some of these bullets will be available near the end of 2007, and will be offered in four different calibers beginning 2008.
Initial Tipped TSX offerings:

Caliber Weight
.270 110, 130
7mm 120, 140
.308 130, 150, 168, 210
.338 210, 225

Why couldn’t they offer something in .257!!!!!!!!!

In dog years - I would be dead.