Console Aim Assist Not Working

Yup - I tried many settings.. turning it down, etc.. it simply won't snap or line up to the enemy as it should..and the reticle always moves off the target before firing... it's like I need to have pixel-perfect adjustment which is nigh impossible in the heat of battle causing many funny moments and controllers hitting the couch in frustration.  Played Halo this morning and it was night and day in terms of aiming and shooting! - and seeing this in the forums...glad to know its not just me.