When Battlefield 4 was officially unveiled last week, the only release timeframe given was "Fall". Microsoft's Xbox 360 blog is being a lot more specific.
It says that "Battlefield 4 will arrive on the Xbox 360 on October 29, 2013", which while far from a guarantee - there's a lot of time between now and October for delays and release changes - does let you know what EA is aiming for at the moment. At least for the Xbox 360 version.
Though it does also make you wonder if October 29 could also be the release date for something else...
EA and DICE Reveal Battlefield 4 [Microsoft, thanks Greg!]