Huum, some Battlefield 1 estimate looks really big.
Battlefield 3 sold less than 2 million first week back in 2011. Considering we are talking about retail alone, so a good part will be eaten by digital, i would be a bit surprised if Battlefield 1 beat Battlefield 3 launch at retail, considering Battlefield 3 was the best selling game of the series...
Though NPD has 2 weeks of track for Battlefield 1, while Battlefield 3 in October NPD 2011 only sold for one week.