BWalker, went to the reloading room and got several samples. The bullet pictured, doesn’t appear to be a “true” boat-tail....but doesn’t appear to be a flatbase either. Not sure, what the heck it is!
Top to bottom: .375 - 250 TTSX. .338 - 225 TTSX. .270 - 140 TSX BT. .375 - 270 TSX FB