Higher speeds can be attained if the skydiver pulls in his or her limbs (see also freeflying). In this case, the terminal speed increases to about 320 km/h (200 mph or 90 m/s), which is almost the terminal speed of the peregrine falcon diving down on its prey. The same terminal speed is reached for a typical .30-06 bullet dropping downwards—when it is returning to the ground having been fired upwards, or dropped from a tower—according to a 1920 U.S. Army Ordnance study.