I have been useing Mirka p1500 for sanding prior to buffing then I see a chart showing P1500 is = 750 American Grit . The 3M rubbing compound says it is good for removing 1500 grit scratchs . is that P1500 or American grit 1500 .

YOu gotta watch the mirka there... I bought a pack of 1000.. not P1000 so it should have been 1000 grit... it was indeed 500 instead... your P1500 should be around 800 grit... to coarse to try and buff out.. if you are unsure compare brands rub some 1500 by 3m and then rub some 1500 by mirka... Once I get above 800 I dont use Mirka unless it is on the DA and 2000 and above grit there after..

I really like the Norton Black Ice paper for color sanding at 1000 then I switch over to 2000 with Nikkens Paper that is re labled Mirror Glaze "Unigrit".... Best paper around, but a dollar a half sheet