Hi Troy and Mod CJ,
When I first opened this thread up and looked at the photos, the first thing that popped into my head was Model 46. It's amazing how similar they really are. I suspect a bit of plagiarism here from one end or the other as you couldn't get it that close without taking ideas in the first instance.
Back then Australia and the USA were far enough away from each other and litigation wasn't rampant like it is today, thus things were done with no repercussions, or alternatively maybe there was some sort of collaboration that we're simply not aware of.
It's an interesting topic I must admit.
Cheers,
BB.