I'm looking at the truglo pro series magnum gobble dot adjustable sight for my 870. They are listed to fit a 1/4" rib so I measured the rib on my 870 and it's measuring .290". I'm a machinist so of course I measure with micrometers, lol. I'm thinking most people measure with a tape and it probably measures 1/4" and I'm sure truglo knows the rib is not 1/4". Or maybe they are and I have an oddball, because that would be my luck. Anyone else have an 870 and did you order the 1/4 model? I just want to be sure before I drop $50 on some sights.