hmm at least what is your jirachi speed ?
i use Choice Scarf on gallade speed boost 50 % or 1.5 my gallade speed 259 x 1.5= 388 speed stat . a jirachi ev'd with the right speed nature will get max 328 speed stat. hmm jirachi was not hold a choice scarf that mean (i think) your jirachi is hacked man =/