Well, I think this article may clear it:



"The No 2 round body, which is available in 12- and 20-bore (as tested here), was introduced much more recently. It is, essentially, the No 2 that so many know and love with the sharp edges removed. Round-bar guns were (and are) most famously produced by Boss. A rounded bar is a means of streamlining an otherwise conventional sidelock or boxlock and sometimes removing a little weight.
To dispel potential confusion, it is not a round-action gun (as built around a trigger-plate mechanism and bow mainsprings)."

Read more at http://www.thefield.co.uk/reviews/review/aya-no-2-round-body-shotgun-review#KCla4kokTlizX0Eh.99

It's a round-body...!

Cheers,
gunwolf

http://www.hunting-heritage.com