Which Screw Is Right For You?

Which Screw Is Best For Your Picatinny Rail Base?

Let’s talk screws… In the world of picatinny “style” mounting bases there are predominately two types of screws used to mount such bases to the firearm. Why did Outerimpact choose one over the other? Good question. We have studied both screw types and have found one provides more positive engagement with the rail being mounted. Let’s explore why. First we need to break mounting screws into two categories. Type 1: is the Weaver style screw. Type 2: is the Socket/Fillister screw. Below is a CAD model of each type of screw.

Illustration of screw definition
Illustration of screw definition

As we look above at the different screw types we see the differences in the head shape. Specifically, we are looking at the amount of screw that is engaged with the rail. Below we can see that the amount of screw head that contacts the rail is greater in the Weaver style screw. Also, if you draw your attention to the shape of the Weaver style screw we can see how it locates itself in the center of the hole. This allows for equal surface engagement around the entire diameter of the screw head. The Socket/Fillister style screw can be shifted in the hole, which allows shoulder of the screw head to be unequally engaged around the diameter of the screw.

Illustrations of the amount of screw engagement
Illustration of the amount of screw engagement

The amount of material below the screw head varies greatly between the two types of screws. One can observe that the amount of material (depicted in blue) below the Socket/Fillister screw is less when compared to the Weaver style screw. This extra material makes the rail more resistant to the screw being pulled through the hole.

Illustration of the amount material below the screw head
Illustration of the amount material below the screw head

From the above illustrations, one can conclude that the Weaver style screw makes more sense. It offers more screw engagement with the base material, leading to a more securely mounted Picatinny rail base – to the firearm. That’s why at Outerimpact we only use the Weaver style screw on our Picatinny Rail Bases.


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