Airsoft, meet water balloons
An idle thought as the boys were target shooting, and the sun was just so. 20 minutes later, we have these. Mostly 1/6400s, and ISO 1600, using an f/4 zoom at between 250 and 400mm approx. The blue dye ones are hugely pushed in post, as they're so dark. Work a treat though. Extra points for the "moment of impact" shot.
Cat unimpressed.