I got blackops 2 the other day and rapid fire is very effective in the game. It seems they didnt try that hard to block mods unlike MW3. I'm pretty sure jitter works too because you can shoot as soon as you switch weapons while in MW3, you have to wait a second before shooting. I'm using flex rf on blackops 2 and the magic speed is somewhere around 8 sps. If you go too fast, it will get mod blocked. I'm not sure if there are any 3 round burst assault rifles but there is a 3 round burst pistol for jitter.