HighTec,Start off shooting BB guns around them as little pups,when they are eating.Banging pans and so forth.I would feed the pups and then set down next to them while they are eating and shoot a low velocity air rifle around them.It does not take them long to ignore the shooting all together.If you have some that continue to shy away just pet them and reassure them.it works on the vast majority of them.Always do this in a envirnoment where they can not escape to a dog house and hide.They need to face thier fears.After a certain point ,I would shoot CBs and then reward the dog for coming to me.It works really well.