Shooting Gazette: How can I improve my cartridge-to-kill ratio on high birds?

In his Expert Instruction column in the Shooting Gazette, this month Adam gives an expert view on the question: ‘How can I improve my cartridge-to-kill ratio on high birds? I’m not a bad shot but I really don’t seem to hit many of these really high birds. Do I need to give them more lead, have longer barrels, heavier loads or is it more about reading the line better?’

Expert Instruction (Shooting Gazette November 2016)