Okay, I don't actually take delivery until 28th Feb so these are not my pics, but my Owen gun is finished!!
Meet Evelyn:
This earlier photo shows how she strips down for storage:
Internally it's an ASG Sten Mk2 with a modified hop up. That means a modified ver7 gearbox. It takes MP40/Sten magazines. The entire hopup/barrel assembly can be removed using the barrel release catch, as you would on the real steel gun.
The Owen gun was the Australian equivalent of the Sten or the M3 Grease gun. It featured a vertical mag as this allowed mags to be changed whilst prone. The Sten also allows easy mag changes whilst prone but a mag in the side of the gun makes it more likely to catch on vegetation. A vertical mag also improves feeding. Unlike other submachine guns of it's era, it has the cocking handle in a separate section of the receiver from the bolt. The bolt will jam if dirt gets to it and the slot for the cocking handle is the most likely place for this to happen. This is the reason for the removable front end, as to strip it you have to take the bolt out from the front. In trials it was pitted against the Sten, Thompson and some german submachine guns, after immersion in sand and mud only the Owen would still fire. The design was not as cheap and easy to produce as the Sten, but Australia was in a very different position to the UK in that they were more self sufficient in terms of raw materials and their factories were not getting bombed.
Incidentally Evelyn Owen was the guy who invented it, hence my choice of name for this gun.