what shafts were used in the Callaway x 16 irons?
The X16 irons came out in 2003 and the stock premium shaft they used was the Rifle. At the time it was manufactured by Royal Precision. True Temper didn’t buy Royal Precision until 2006. If there was a stock non-premium shaft offered in sets of the X16, it could have been similar to the TT Lite, but I do not know that for sure.