Mounting a Red Dot sight

What could be better than slapping a Red Dot sight on a fully ambidextrous bullpup auto repeater and engaging some fast and close targets with rapid-fire heat. The Desert Tech MDRX is compact, versatile, and swaps calibers faster than an Arizona swinger. There’s no doubt that a variety of sighting options will best suit this platform and a Red Dot mount on an MDRX is a no brainer.  

Red Dots function with a singular focal plane which means when your eyes are focused on the target they are simultaneously focused on the reticle.  They also benefit from reduced parallax so that movement of the shooters head has little to no effect on the position of the reticle.  And there is also no eye relief with a Red Dot, which means positioning of the shooters eye, close or distant to the optic, isn’t important. For these reasons the Red Dot is very forgiving, incredibly user friendly, fast for newbies and pros alike, and incredibly accurate.  

“Red Dot Sight”, or RDS, is a general term used to describe a variety of optical sights including Reflex, Holographic, and Prismatic.  Some Red Dots have green reticles or a crosshair pattern instead of an actual dot.  Whatever the particulars, the basic principles are the same.  If you are new to red dots, here are a few tips to get you started with mounting and zeroing so that you can get the most out of your rifle without too much messing around. 


How far forward or back you mount your red dot is going to depend on a few things like whether or not you plan to use back up iron sights, a magnifier, and just plain personal preference. Mounting on the forward half of your rail will work best to provide real estate for iron sights and magnifiers. Keeping things closer to the rear will provide better balance and a larger field of view. You might even want to briefly experiment with a couple locations doing some dry practice and see what feels best. After you find the sweet spot, you’ll need to lock it in place. If your optic is a bolt-on type, then it’s a good idea to use some blue (not red) thread locker. Metal-to-metal contact with threads in combination with recoil will undoubtedly loosen the fasteners and your red dot will start flopping all over the place and performing poorly.  Make sure and follow any torque settings recommended by the sight manufacturer. Mounting a red dot is much simpler than mounting a traditional magnified rifle scope. There is no need to worry about misaligned scope rings or crushing the tube. It’s nearly a failsafe endeavor. And if you have a quick release mechanism, then the whole affair is a non-event.  


During the “zeroing” process consider turning down the brightness of the reticle to the minimum that is visible. Reducing the brightness will in effect shrink the reticle and provide a more precise point of aim and obscure less of your target.  Next, you’ll want to pick a distance at which to calibrate the zero. Depending on the type of shooting you plan to do this will be closer or farther away. A 30 meter zero will work well for tactical types of shooting or competition where many targets are relatively close, and the odd long-range shot can be taken by simply aiming at the top of the target.  If you take a shot at a distance significantly closer than your zero keep in mind that you will also have to compensate.  For example, a target at 15 yards will require the shooter with a 50 yard zero to aim a little high, similar to compensating for targets beyond the zero distance. This is because of something called “mechanical offset” or “sight over bore height”.  Compensating for mechanical offset is a whole topic on its own and a prime subject for a separate article. At the very least keep in mind how you plan to use the rifle and at what ranges you are most likely to engage targets. It’s a good idea to at least practice shooting some targets at very close range to get an idea how your aim point will shift.  Next comes the fun part: Shooting groups and adjusting windage and elevation. 

The easiest way to work through this is by setting up a nice paper or cardboard target at your specified zero range.  Then stabilize your rifle with a bipod, sandbag, or other rest and take a single shot as precisely as you can.  Pay attention if your misses are landing off the paper and where they land.  It helps to have a spotter.  If you are hitting too high or too low, then adjust the elevation setting.  This might require removing a dust cap and using a screwdriver or hex tool.  If you are hitting left or right of your point of impact, then do the same thing with the windage adjustment.  Once you get your shots landing in the 10-ring, try shooting a five-shot group just to confirm.  When you have a consistent pattern of dead nuts hits, then you are good to go. The final step is to find a range, sling some lead, and listen to the sweet sound of ringing steel.

Red dot sights are just plain fun.  And pairing one with a rifle like the MDRX is ideal because it aligns so perfectly with its broad performance envelope.  Red dots give you the opportunity to better utilize the rifle with a close-quarters, fast firing approach in mind.  And once you have it set up, swapping it out for another system, better suited for a long-range approach, takes only seconds.  If you’ve never used a red dot sight, give it a try, and you might find your 25x optic collecting dust.

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