http://en.wikipedia.org/wiki/6_mm_SAW
check the link the 6mmTCU is totally different from the SAW cartridge
and read the links inside the link i posted above also the 6x45 can barely reach 3200fps with a 60gr bullet and just a tad over 2600fps with a 100gr bullets so its about equivalent to a 223 with a 55gr and 90gr bullets