A Guide to Magnifiers: Co-Witness Heights, Distance Between Red Dot and Magnifier, and More

A Guide to Magnifiers: Co-Witness Heights, Distance Between Red Dot and Magnifier, and More

May 21st 2023

Magnifiers are great accessories for enhancing your shooting capabilities, but to fully utilize their potential, it's crucial to ensure proper alignment with your red dot sight. This article will guide you through identifying the ideal height for your magnifier, the optimal distance between your red dot and magnifier, as well as the installation and fine-tuning process.

Identifying the Ideal Height for your Magnifier 

When aligning your magnifier to your red dot, the crucial first step is to match the height of your red dot and magnifier. Our Ghost magnifiers mounts for example are built to absolute co-witness height which is 1.42 in or 36 mm. Height matching your red dot and magnifier offers several benefits that contribute to improved shooting performance. By aligning the heights of these optics, you ensure a consistent sight picture, allowing for seamless target acquisition and engagement. Various standard heights are available to accommodate different firearm setups and shooter preferences and is something to keep in mind when ordering a red dot or magnifier to avoid additional costs in riser mounts. If you already have a red dot and want to match it's height, we provide riser mounts as well as absolute co-witness mounts for micro red dots if you have spares laying around and want to put them to work. 

Shown above is the Sentry Micro Red Dot Riser Mount, it is made specifically for RMR or Venom/Noblex Footprints and features side shields to protect your red dot. We also have the Shrapnel Micro Red Dot Riser Mount and sets your micro red dot at absolute cowitness height. 

If you want to achieve absolute co-witness height, keep in mind that it is a height measurement which measures from the red dot, or reticle when co-witnessing prism scopes, to where the mount touches the base. Some common errors when measuring this would be to measure from the reticle to the end of the mount or just measuring the mount itself as demonstrated in the graphic below. It doesn't have to be perfect as any good magnifier should have fine-tune turret adjustments to adjust the picture and compensate for slight height discrepancies. 

For absolute co-witness, this measurement should be around 1.42" or 36 mm; for 1/3 lower co-witness, this number is 1.59" or 40.4 mm.

If you are going for a lower 1/3 co-witness setup, you may need an additional riser mounts for the magnifier and red dot to push the height up to that level. These setups are ideal for those who want a more relaxed position for neck relief or desire a less cluttered sight. The official height for a lower 1/3 co-witness is 1.59 inches or 40.4 mm, while the official height for absolute co-witness is 1.42 inches or 36 mm. 

Distance Between Red Dot and Magnifier 

The ideal distance between a red dot and magnifier depends on individual preferences, shooting style, and the specific optics being used. Good magnifiers have a generous sweet spot, but ideally, the magnifier shouldn't be so close that you can no longer use the flip-to-side mechanism and not too far leaving you with little room for eye relief when shooting. Comfortability and usability is key for this distance. 

Installing your Magnifier 

Once you've identified where you want to mount your magnifier, it is time to secure it. Each manufacturer may have different mounting systems and torque specifications. Monstrum recommends 30 in-lbs of torque for our magnifiers and blue threadlocker is advised but not required. 

Fine-tuning Your Magnifier

All Monstrum magnifiers come centered from the factory but a number of variables can cause your picture to appear off-centered. An example of this would be if your red dot and magnifier have very close heights but not exact. This is where the adjustment turrets come into play. By dialing the turrets corresponding to windage and elevation, you can get the picture centered on your magnifier. Check out the graphic on the bottom to see some examples of this. [Insert graphic with misalign magnifiers] And that's really all there is to it. We carry a variety of red dots, magnifiers, and riser mounts to make sure your setup is as optimal as possible.

And that's really all there is to it. We carry a variety of red dotsmagnifiers, and riser mounts to make sure your setup is as optimal as possible.

Final Thoughts

If you are new to magnifiers, you might notice that the edge of your picture might not be sharp, this is normal. Unlike scopes where the entire optical system is sealed, there is space between the red dot and magnifier and this allows light to pass through resulting in a less than perfect edge. If you want perfect edge-to-edge picture, scopes make a better choice, but you will sacrifice red dot capabilities such as not having to worry about parallax and eye relief. For those who have a hard time adjusting to this, we have our MarksmanBlackbird, and Raven series of prism scopes feature low level magnification such as 1.5x and 2x that offer generous eye relief for easy rapid target engagement.