For my pennyworth, I tried the old X bullets a few years back and whilst they performed well, accuracy was not all it should be. I have recently tried them again in the TTSX and wow what a difference. I am now a complete convert. Yes they do cost a bit more, but the trade off in accuracy and lack of meat damage more than compensates. I use a 120gr in my 7RM and this gives me a very flat shooter out to any sane range, and the 100gr in my 6.5 x 55 has transformed it into a very efficient deer culling machine. On the range I regularly get ragged holes from both rifles. (By the way no custom rifles just Pro-hunters).