Expert archaeologist, Tim Malim says the live fire exercises that took place on practice trenches at the hillfort near to Park Hall Army Camp more than 100 years ago, may have been essential for the war effort but terrible for the preservation of Iron Age artefacts.
A small group from Oswestry Heritage Gateway Group spent four days completing the excavation with permission from English Heritage and Historic England.
They say improving the management and conservation of "Old Oswestry" on the northern fringe of the town, could boost cultural tourism.
This was the second season of investigation following on from excavations through two of the ramparts last year.
Tim, from Hampton Heritage Design & Consultancy, said the team focused on relocating remains of a roundhouse that was originally found in 1940, so that samples could be retrieved for scientific dating techniques that were not available then.
"The roundhouse was constructed with a clay floor and large posts set into holes in the ground and packed around with earth and stones - a reconstruction can be seen at Park Hall Experience.
"Charcoal from Iron Age cooking fires was also included in the posthole fills, and this has provided samples for radiocarbon dating. Further evidence for housing was found in the back of the stone and earth rampart, which including fragments of daub, fired clay from the walls of a roundhouse. These fragments can also be helpful through the use of thermo-luminescence dating techniques."
He said that the back of the rampart had been marked out by a line of kerb stones, and the main part was a bank made up of large stones and clay, which is now used as a footpath around the top of the hillfort.
"Although the excavation only lasted for four days, 10 volunteers worked with great enthusiasm and dedication to achieve these results. A geophysical survey completed last year and available to view on the Old Oswestry website, shows significant World War 1 activity, as well as some potential Iron Age remains.
"Evidence for use of the hillfort interior by Park Hall Training Camp soldiers is visible as backfilled trenches on air photographs and in the geophysical survey, and also by the many pieces of shrapnel and rusty iron found during the excavation.
"It is clear that live fire exercises were conducted on the site over 100 years ago, essential perhaps for military training, but unfortunately terrible for the preservation of Iron Age archaeology at the hillfort."
More information can be found in a book was published in 2020 “Old Oswestry Hillfort and its Landscape” which is available from the Willow Gallery or Booka in Oswestry, or online from Archaeopress.
"This includes a chapter on how Oswestry Heritage Gateway sees the huge potential the hillfort and surrounding landscape has for social and economic benefit for Oswestry and surrounding communities. Working with English Heritage, the High Street Heritage Action Zone, BID and other partners, Oswestry Heritage Gateway seeks to improve management and conservation of the hillfort, and to promote the value of cultural tourism that its surrounding historic rural landscape can bring to the region."