I'm glad the prong and leash corrections work with your dog, but I would never suggest this to someone with a 4 month old puppy. First because it should be used as a last resort, and if the puppy is four months old you have not had enough time to train him sufficiently to decide that you need a last resort method already. Second, this age could be the puppy's fear stage, and you should never use punishment methods like this while the puppy is in a fear stage, it will cause bigger problems down the road.
If the turns and stopping don't work,and the OP feels like she needs different equipment to teach the dog, I would suggest a no pull harnes.