The Charlton automatic rifle is one of very, very few examples of a conversion from bolt action to self-loading rifle actually working reasonably well. Typically this sort of project founders in expense and unreliability. Charlton, however, was able to take his vision for providing the New Zealand Home Guard with a new weapon made form obsolete surplus and bring it fully to fruition, with 1500 guns made. They were never fired in anger, but allowed New Zealand to put all of its Bren guns into the field while retaining Charlton as emergency weapons in case of Japanese invasion. Sadly, virtually all were destroyed in a warehouse fire after the war, leaving them extremely rare today.
Many thanks to the Royal Armouries for allowing me to film and disassemble thevery scarce automatic rifle! The NFC collection there – perhaps the best military small arms collection in Western Europe – is available by appointment to researchers, and you can browse the various Armouries collections online.
For the whole detailed story on Charlton manufacture, and to download a copy of the manual, check out my full article.