pretty simple why the plastic safety button breaks.....look at it, it's plastic and between the screw hole and the adjacent edge there's just no meat, then compound it by tightening down a screw head right where it's skinniest......yea they break. It's a easy fix.If you can disassemble your reciever and use a screwdriver you can do it. I bought a metal button from havlinsales($10) configured just like the plastic button and a hex head cap screw in 6/32. The screw was too long but i used the old screw to fit for length,cut down new screw, reassemble safety. The head on the cap screw was thick enough so when it;s tightened down top of screw head protrudes slightly above button body giving me a little hump for more purchase.....you can buy a fancy expensive safety button if you choose but really all you need is a replacement metal button. And don't put that doggone one way screw back in.....all you really need is a 6/32 screw the right length with a head that will fit in the mortise of the button for the screw head. There''s no need to pay a gunsmith to install a Mossberg 500 safety.......Mike