I recently purchased one of these 870 HD 7 Shot.
I have already added a Surefire forearm light (FP618A me thinks...) and a 6 shell Side Saddle.
I think I'm gonna keep the factory stock, and I'm looking for a decent tactical sling.
I will be carrying it as an alternate long arm on a security job for about two weeks, so looking for something that offers some comfort or the ability to swing it around to sit across my back.
My first attempt at linking a pic..
If you haven't already found a sling, you might want to look at CQB Solutions/Specter Gear. They make 3 point tactical slings for almost everything. If memory serves, shotgun slings are about $36.