I have a 42 mm Red Dot($20 from Walmart years ago and this gun has only seen 3.5`) on my dedicated 870 and will second the fact you can adjust your pattern. Also with a Red Dot there is no concern of form when you shoot, just put the dot on them and giver. I have shot few turkeys when in a comfortable shooting position, usually twisted around, sometimes left handed. on your belly, slouched sideways, you get the idea. My gun shot consistently left, not much but enough to be a concern and the Red Dot fixed that.
The gun and load must be matched as they do not all preform the same. I have shot an Undertaker choke for years and it performs from 0-55yds as it should. From 0-15 the pattern is golf ball size so practice a couple in close so you know how tight it is on those 3 yd birds. When you find a ammo combo that works my advice is to buy lots as sometimes material changes are made year to year. Got me one year when the brand I use changed the wads and unknown to me it made my gun shoot 12 inches right. Missed 5 birds before I thought to put the gun on paper and it was then I shot an old shell right on, the new box 12 inches right and when walking to the patterning board noticed the new wad. Twist of the Red Dot fixed it but it was a humbling experience on not trusting ammo manufactures to keep things the same.
