I always take such claims with a pinch of salt - measuring where a bird fell is often no accurate indicator of where it was killed. I shot a hen pheasant in December overhead that fell dead around 120 yards behind me - it was a high bird but it was not 120 yards up!
Ducks a good way up on a windy day are apt to fall a long way from where they took lead.
Where you do get more accurate ideas of killing range is in the pigeon hide decoying birds that cross the periphery of your pattern or approach low from ahead. These birds do drop dead within a yard or two of where they are killed. Once in the swing, I have found I can kill pigeons as incomers and crossers at 45-50 yards with fair regularity using I.C and fibre wadded Game Bore Pure Gold No.6. Whilst using a tighter choked dickson round action this past summer, I found that teh same loads were killing well out to 55 yards. The trick is getting the lead right. A good pattern will hold up at 50 yards but you need to be right on your bird, thus incomers are killed better, the shot string is mostly heading for the target if you are on it.
