About 15 years ago, I put a set of those very sights on a 24" Mossberg 835 to be used as a turkey gun. I used finger nail polish to set the screws, and the whole arrangement has been solid and stable ever since. I was a bit concerned that the fiber optic tube on the front sight would prove fragile in the sometimes frantic run and gun nature of some hunts, and the crashing about in the pre-dawn woods, but everything has held up very well. I hunt the Mossberg with the fiber sights a good bit every spring.
I too have trouble with standard bead and blade sights these days, especially on short barrels, but as Natman stated, I can line the fiber optic dots up on the shotgun well enough to prove the demise of any gobbler that wanders by inside 45 yds or so. (well.....most of the time
)
Natman raises a valid point, to a certain degree anyhow. Fiber optic sights gather light, if there is no light, your sights will not be "lit". Will the "unlit" sights be visible, I dunno. The counterpoint is that if there is not enough light to identify your target, you should not be shooting anyhow. I have not run into a situation gobbler hunting where there was not enough natural light to see the Tru-Glo sights, ,the bird and take the shot. Will there be enough ambient light down a night time hallway, carport and so on to see threat and fiber optic sights in your critical incident, I dunno. Serious SD/HD long guns mount some type of light these days. Will that weapon mounted light supply enough scattered illumination for a set of fiber optic's to work......maybe.
I recently installed a See All sight on a tactical pattern carbine. A simple explanation of the See All's operation is that the sight has a large fiber optic type wafer that gathers ambient light, allowing the chevron type reticle to become visible in one's field of view. As an experiment, at night, I set up a target at 25 yds in front of my pickup headlights, the target and backer were clearly visible. From assorted positions in and around the truck to include in front of the lights, I attempted to gain a sight picture and place rounds on the target.......never happend!
That big chewing gum sized wafer of light gathering material mounted on a rail on top of the carbine was not getting enough light to allow the sight to function.
Were I inclined to add a simple night sight system to a bead sighted fighting shotgun, I believe I would consider the X-S Big Dot epoxy mounted version.