I'm putting a red dot on my 870 for this spring. Used it on my son's 22 and really like it. I'm going to try and get one with a size 10 dot though, the 5 is a little hard to see when it is bright out. I've been looking at a Bushnell Trophy Red Dot , it has 4 different sights, a 3MOA dot, 10MOA dot, cross hairs, and a 65MOA circle with a 3MOA dot.
Although it is a little pricy at $99, but I think it will be well worth it. Just have to wait untill tax return time!!!!!!!!
Mossberg also makes a turkey/deer combo, and a water fowl/deer combo! Comes with two barrels, the deer barrel has the cantilever style for the scope. The Turkey combo has the 24" barrel, the water fowl combo has the 28" barrel. The barrels on the deer I believe are 22".