Two homebuilt pistols were seized among other firearms on Tuesday by police in Sydney. They appear to be of a closed bolt design, using a plastic lower receiver with an angular magazine well. Both examples appear very well made.
To recap, a number of improvised submachine guns have been seized in Australia recently, many based on the Expedient Homemade Firearms series of manuals by British author Philip Luty.
Various .22lr SMGs:
It would be uncivilized not to link once again to a test fire video: