Most of the time when one uses an 8 twist 22 cal barrel it is to stabilize heavy bullets, 75 to 80+ grains. I have a 22x6mm imp 8 twist and I can't keep 80gr Bergers from vanishing somewhere between the muzzle and the target. Went to 80gr SMK's and all is well now.
I would move up to a heavier bullet in that 8 twist barrel, if you are looking for pure speed find a bullet with a thicker jacket than the Berger, the Sierra Match Kings are made with a thicker jacket that the Berger's or A-Max's.
Good Luck
Dave