This practice wall by the Sheriffmuir Road, close to the Sheriffmuir Inn, was used to test weapons as preparation for the attack on the Atlantic Wall in Normandy. Map
To find out more, here are a couple of useful web links.
Stirling Council Archaeology page : Stirling's Finest Hour
Forth Naturalist and Historian (page 107) link to a paper on The Sheriffmuir ‘Atlantic Wall’:An Archaeological Survey on part of the Whitestone Military Range