Getting a 20 inch double.

A "Carbine Double" is what Jason Simpkins calls them, some call them Bush Guns or Stopper Guns.

I do know that the other 20-21 inch barrels on my other guns shoot out to 300 yards if that is what I need them to do, although certainly the top reasons for a 20 inch double have far more to do with quick shots, carry, heavy brush and cover shooting... but then yea it can still perform out to longer distances without sacrificing too much.

Yet as stated above it is much more about BALANCE of the gun. If it balances well at 20 inches then that is a double plus in my opinion.