As Iowawaterfowlerfever knows last year I ran into this with my dog and tell ya what theres nothing more discouraging going out on opener and the dog is gun shy. I shot around mine but nothing like what happened last year. 6 guys in a blind and I was sitting outside x 3 shots at sunrise can be more intimidating to a dog than just shooting a .22 around. and lets just say last year opener was way better than this year.
I talked to very good trainer and he knew my frustration. He said in the 30+ years of training and breeding labs hes never seen a dog ruined. He said hes seen a lot of them that are bad but never one ruined. That gave me hope. I started off banging bowls together while eating, but what I did that helped was got a cap gun. I would get her hyper and praising her and shoot in the other room, soon get closer and so on. then move to .22, and shotguns, but yes I would agree praising, and treats is what fixed my dog and now when you pull up shes fn ready and diving in! good luck man and dont get frustrated it may take time. Mine was fixed last year in 3 weeks, but I work everyday with her.