primary arms offset mount

A primary arms offset mount is a device that allows a shooter to mount an optic (such as a red dot sight) at a 45-degree angle to the rifle's bore axis. This allows the shooter to have both a magnified optic (usually a scope) and a non-magnified optic (usually a red dot sight) on the same rifle, without having to remove one or the other.

The primary arms offset mount typically attaches to a Picatinny rail on the rifle's receiver, and has its own Picatinny rail on top for mounting the optic. By offsetting the optic, the shooter can quickly transition between long-range and close-range targets without having to adjust or remove the magnified optic.

This type of mount is commonly used in tactical shooting scenarios, where the shooter may need to engage targets at varying distances and quickly switch between optics. It can also be useful in hunting situations where a quick shot may be required at close range.