There is prone, and there is Hawkins prone, 73 years ago today
A British Army sniper demonstrates the superior ‘Hawkins’ prone firing position (right) next to another in the standard position, at the 21st Army Group sniping school near Eindhoven, 15 October 1944. Note the scoped Enfields.

Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/205202573
The Hawkins was described by one Tommy as “taking buttons off your shirt to get that much closer to the ground.”