A recent discovery in the library of the Leeds Armouries was this introduction to a comprehensive series of tests on 7,62x51 Duplex ammunition. The rest of the document was largely a series of target showing the shot dispersion that I chose not to copy. It’d take too long for the page to load here to include everything. I hope these might be of some interest.
If anyone would like higher resolution scans please drop me a line together with an e-mail address.
Happy collecting, Peter