Ten bores for close in ground birds and decoyed ducks are not rare. I have ten bore Parkers with hammers, 28" cylinder bored barrels, and less than eight pounds, a 27" ten bore DH Parker at 7 pounds, 4 ounces, and a 26" ten bore Sauer hammerless Krupp gun at six pounds, four ounces. Francotte light tens are not rare either. Some guys ordering guns, back in the day, knew exactly what they wanted.