What ever happened to the quote, "it isn't the gift, but the thought that counts"?
If your wife didn't have the knowledge to get exactly what you wanted, she probably also paid too much. But that's beside the point. Like the gun or not, she still went to some bother to get something she hoped you'd like.....otherwise she would have just given you a gift certificate. Don't be a self-serving selfish jerk and kick her in the face. No way I'd intentionally hurt my wife's feelings for a mere $200. I guarantee you, if you trade off the gun and your wife is diagnosed with cancer the next week, you'll regret your decision for the rest of your life......if not, there's something wrong with you. Be a man, be a good husband and suck it up and act like it's the best thing in your marriage since the honeymoon. Even if you hate it, one of your children might love it and the fact that Mom gave it to you will make it even more special after you're both gone.