A .50 cal round with a black tip, headstamp S L 43. My boys book of headstamps, ok its really DIA Small Arms Identification Guide 1984 says its St Louis Ordnancee Plant and armour peircing. We were topping up feeders in the wood and Archer found it mud encrusted in the middle of a Chestnut Coppice ring. We are wonderng how it got there? Sussex by the sea in case you were wondering, definetly no marks from being extracted. Sorry about the close up, cant work the macro too well!