Guns, Dogs and Blades QnA

Need advice...my background...have an HK 9mm, no optics. No rifles. Just got a Beretta A300 Ultima Patrol 12 gauge for HD, but I want to practice, be GOOD at it. Going to be using Federal LE 8 pellet 00 buck...does a red dot help me any, or not enough? If so, recommendations? I'm leaning toward a Holosun, if I do get one.
Thanks!