2 and 5/32 inches is about 54 millimeters, which got me measuring my 12g doubles, one Italian one English. They both measure 57 millimeters across the breech ends, both have barrel thickness at just over 4 mm at the breech end (just below the rim step). Both of them weigh 6,6 lbs, or 3 kilos. Seems like the source of the extra weight of the RBL 12 is in the barrels more than the action body.
Puzzle is how the RBL 12 can fit the 12 gauge barrels on the 54 mm receiver. The dimensional "squeeze" probably is in the middle part, between the barrels. In the photo is seems like the 16 has a narrower lump than the 12.
