Sometime in the not too distant past I purchased some tritium beads for my HD style shotguns. They were reasonably priced, so they just got added to orders from Brownells. Tonight I decided to get around to seeing what I need to do in order to install them.
First, the good:
The sight for the Mossberg 500 is actually really easy to install. Using a 4mm socket, the old brass bead came right off without any damage. And the Meprolight bead just screws right in. The threads are longer than the old bead sight, so if you tighten it all the way down it extends into the barrel (not by much), but more importantly is not in line with the bore. So, I added some blue loctite, and backed it out enough that it is lined up, which also means it is flush inside the barrel. There is a slight gap under the sight, but it isn't enough that I am going to worry about it, especially after the loctite sets.
Next the bad:
The sight on my Remington 870 Express is apparently pressed in, and not threaded. I learned this before I mucked up the current bead sight trying to take it out. The meprolight replacement is threaded, so I have the feeling that I am going to have to take the barrel to a gunsmith or machine shop, who can hopefully pull the old bead out, and then drill and tap the hole to accept the new sight. I have head some gunsmiths don't like installing these sights, because if you really torque on them the vials of tritium can break.
I think that these are a good addition to a HD shotgun, and if you get the version with a white ring around the tritium it should function well during the day too. However, I am much more pleased with the ease of installation for the Mossberg 500 than the Remington 870. I generally don't have a dog in the "which is a better shotgun fight" because I like both of them. But, right now, I like the Mossberg a little bit more.