Holographic sights have no parallax where red dots do. When using a shotgun at short range this does not come into play. Either would suit you well. I would focus more on the features. If I would choose one, I would have a green dot option with a large circle around the center dot. I would also have a large viewing area. I personally would avoid a "red dot" as a turkeys head is red and could blend in to easily. I would look for good battery life and a scope that does not shut off after 5 mins. Some of them out there turn on with movement and others are manually turned on and stay on for 30+min. Price is also a factor. The only holographic that is on the market that I am aware of is EOTech. They are built like a rock and are used on military weapons but they will run $450+. My old man recently put a Sightmark red dot on his 870. It has all of the features that I like and it runs $75 to $100. If I had the money I would choose a holographic but a red dot is very suitable for shotguns and turkeys. I personally have a Nikon Turkey Pro BTR variable zoom scope on my 870. What I like about a scope is that I can look at the turkeys close up and easily choose the bigger one. I would never go without a scope after using one. Remember, you get what you pay for.
