If any of you add sling studs to your 870HD, let me know how it goes. I've been contemplating the addition of some Uncle Mike's studs to two 870s with synthetic stocks, but I've been a little wary of getting the hole crooked. There's only a small bit of internal plastic to accept the stud (those stocks are mostly hollow), and the hole needs to be perfectly straight. If I had a drill press, it would be no big deal, but I don't own one.
My closest local smith doesn't like the Uncle Mike's stud package. Instead, he insists on drilling the existing mag cap and adding a stud to it. Charges about $35 if I remember right. I've never heard any complaints about the Uncle Mike's stuff though, so I may just add one myself. Still, gotta get that hole straight, and you only get one shot...