I'm looking into a sxs made long ago in UK by a good shop. The barrel flats indicate bores measure .729 and .740. It was reproofed in London in 1983 for 2-3/4" chambers at 3-1/4 Tons and 1-1/8 ounces of shot. Cannot see any indication the bore size was changed over the life of the gun. Perhaps the gun required reproof because the bore was .740? (12 ga). The gun is expensive, so it may behoove me to get the original documentation for this gun before purchasing it...