As a contemplative novice saving for a double, I have a couple of questions about the Merkel 140. Please pardon my ignorance, but are the barrels round or octagonal (yeah, I guess they're round on the inside!)? If ejectors are an option, is it much dearer? Also, does anyone know if it is available in .500NE in Australia? The website for Hermann's only lists .375 H&H, .416 Rigby and .470NE. Thanks for your time!