Pretty interesting - Meprolight FT Bullseye Tritium Self-Illuminated Rear Pistol Night Sight

I really like the visibility of this in the day time. but when I put it on, and when I line up the dot and circle as designed, my shooting is way off not. like I have to totally re-sight my using the pistol from what I was used to before. so much so that I need to get a laser bore site and put it in the barrel so I can look thru again and figure out where its pointing. once I establish that and know that's how this gun sights, then it should be fine. but I had no idea it would change it so much by swapping out my OEM sight to this. I like it because it's so much more visible. and it's radioactive, how cool is that? eventually it will die, it says 12 year warranty. I put the geiger counter near it and could not detect anything, so it seems safe. what a world we live in now!