I have purchased a Winchester Select Energy Sporting O/U 28inch gun as my new trap gun. I have gone to 2 different practices and have performed poorly and i need to find out why i am not shooting as well as i usually do. I went from a Field Model O/U and wonder if going from a field to a sporting model is what is affecting me. Please tell me whats going on. And what kind of choke should i use, i have always used a modified.