Have a look at the other thread on here. There is some good info there.
Remember when introducing a dog to a gunshot the two must have distance between them.
1. I used to take our pups to the trap range and park the vehicle a 100 yards away. Note: dog still in his kennel. Slowly work closer over a few weeks until you have the dog on a leash watching the shooters.

2. Initially introducing marks the thrower would give a hey/hey and throw the bird. Than over time we would introduce a blank pistol until we eventually worked up to poppers.

If you read the other thread read Doc's message and check out the link.

Scott