You should consider high-power rifle competition, especially on military facilities (longer ranges). Granted, it's not what you're really looking for, but it may be the best you'll find for long-range practice. And it is good practice. Further, you'll find the comraderie outstanding, and folks will help you develop your skills. When you learn to read wind and light, and improve your scores, you'll find that much of what you learn transfers well to the game fields.