The Bushnell Banner scope works well on shotguns, I have a friend that uses the Bushnell Banner 1.5 - 4.5 x32 on his and he loves it.
As far as the call freezing up on you, If you're wearing it around your neck try keeping it tucked in your jacket after calling
that should help, otherwise, just keep it in a jacket pocket. Good Luck to you.
Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the outcome of the vote.