The red dot mount should properly fulfill the purpose for which you use the firearm. Based on this, there are different types of mounts.
Fixed mount (bolt-on)
A simple and lightweight construction that you will appreciate if you want to attach the mount to the rail once and not deal with it further.
Adjustable mount
Allows you to adjust the height of the optic so that it is aligned with standard iron sights, or lower or higher according to your personal preference.
You can therefore use iron sights and a red dot simultaneously (co-witness), set the red dot into the upper third of the field of view (lower ⅓), or position the red dot higher if you have tall sights.
Offset 45° red dot mount
This mount positions the red dot at a 45° angle relative to the primary direction. It is used when your primary aiming solution is a rifle scope or another optic.
In this case, the red dot serves for rapid target acquisition at short distances, achieved by rotating the firearm by 45° instead of changing head position.
QD Picatinny red dot mount (quick detach)
A quick-detach mount that can be removed from and reattached to the Picatinny rail without any tools. After reinstallation, it retains zero without the need for re-zeroing.
Ideal if you want to transport the firearm without the red dot attached or if you alternate between different optics, ideal for tactical shooting.
Red dot compatibility
Red dots differ in their footprints, which define various screw spacing, recoil lugs, mounting surface dimensions, and more. To ensure that your red dot fits the mount, choose one that is compatible with it.
Not every red dot has its own footprint, and there are several main types with identical parameters. With the Bren 2, you will most commonly encounter MRA, MRO, Aimpoint Micro, and Trijicon ACOG footprints. However, classic pistol red dots can also be installed, which commonly use footprints such as Trijicon RMR, Leupold DPP, C-More RTS, or Shield RMSc.
To be sure that your red dot can be mounted on the mount, verify compatibility in the product description.
Can I install a red dot mount myself?
Yes, it is a very simple firearm modification that requires only an Allen key and a few minutes of time. You simply place the mount into the slots of the Picatinny rail and tighten it according to the instructions. With a QD mount, you do not need any tools at all, as it is secured using the quick-release mechanism.
Afterwards, you perform zeroing at the shooting range and set the zero. With a QD mount, you then do not need to re-zero again, as it reliably retains zero repeatedly.
