According to Official Guinness Records,
The most basketball three-pointers in 24 hours is 10,381, and was achieved by Daniel Loriaux (USA) at Club Sport Oregon in Tigard, Oregon, USA, from 30 June to 1 July 2012.
Daniel took 13,718 shot in total. His shooting accuracy for this attempt is 75.67%
For a complete list of 2012 records, please visit 2012 Guinness Records in United States.