First of all congrats on selecting one of the best defensive shotguns on the planet. But holy smokes do you open a pandoras box with your optic question! First thing is how do you intend to use it? If it is real life home defense I would look at perhaps a visible laser. But if you are going to invest in going to defensive shotgun classes a red/green dot optic is your friend. It will help facilitate your training. I fully realize that seems like a contradictory statement given usage. But again you must be honest with yourself with regard to context. If you are running drill after drill running and gunning you need the optic. If it is leaned against the corner in your bedroom, and you grab it, and go down the hall at zero dark thirty you likely may never even shoulder it. Thus the contradiction. In the event you go optic and choose Holosun I would sure look at a 510 for your shotgun. Perfect match. I would also look at an extra shell magazine, me personally I like the stick on Velcro kind that I can rip off and toss another loaded one on. Ping me if you need vendors, there are many! Again my apologies for long winded answer! Great shotgun!