Description

This is the old Flat Blade Driver type screw for Front sights used on Mark Series Bull barrels.
Ruger switched to slightly longer Allen screws in maybe 2017
This is 6-40 threads, NEWER post October 2019 Mark IV STEEL barrels use a 6-48 screw so PAY ATTENTION!

***IF YOU HAVE A LITE***
The Ruger LITE currently uses a special longer front sight screw because the upper is aluminum and these shorter screws could easily strip the threads out of the upper.

These longer screws are HERE