Steering ammunition for .50 BMG

The US military development forge DARPA is currently working on a guided bullet project for snipers (EXACTO), and the initial public test results in the video look promising. The new ammunition is caliber 12.7x99mm (.50 BMG) and was likely chosen due to the projectiles (significantly larger and heavier than e.g. .338 Lapua Magnum) and the prevalence of the M82A1 rifle (and its successor models).