Hi, I live near a former WW2 US airforce base. Over the years I have picked up hundreds (probably thousands) of .50 cal heads and casings. All of the casings are marked SL 42 and most of the projectiles are either ball or tracer (the most common being ball). Amongst the heads that I have found is one with a segmented base. Unfortunately it has started to split along the segment lines, as the innards rust. It still looks quite different than the others and therefore interesting. Can someone please tell me what type of projectile it is. Thanks