Implementing Red Dot Sights for Your Agency

Ron LaPedis

Red dot sights place the target and the reticle roughly on the same optical plane, allowing a single point of focus. This enables fast acquisition and allows the officer to keep his/her attention on the field of view in front of him/her.

The results of a four year handgun Red Dot Sight (RDS) study by Aaron Cowan of Sage Dynamics show substantially increased hit accuracy using an RDS over iron sights. Multiple agencies which have issued an RDS to trained officers are seeing the same trend. Higher hit accuracy equals lower collateral damage. And, this is a good thing.

The key word here is “trained.” An officer with an RDS equipped sidearm is the destination – and there are many steps needed to get there. Slapping an RDS onto an officer’s pistol without taking time at each stop along the way is a lawsuit waiting to happen.

Let’s look at the activities needed to get RDS into your agency:

  • Train range staff how to select an RDS.
    • Footprints
    • Select a sidearm/RDS/holster system.
  • Train armorers and range staff how to mount and sight an RDS.
    • Test fit the RDS using an adaptor plate, if necessary.
    • Properly mount the RDS.
    • Properly sight the RDS.
  • Train range staff to teach RDS tactics.
    • Train sworn staff.
    • Train recruits.


1. Train the Trainers (1)

The first train the trainers activity is to give your rangemaster or range staff enough information to perform a needs analysis for a move to RDS. The odds are high that your current issued sidearms may not support an RDS or, if they do, they may not support the RDS you want. How can a sidearm not support the RDS you want?

While there is no single standard for the mounting footprint of an RDS, the good news is that the industry seems to be coalescing around a handful of more popular footprints. For example, many sights use the Trijicon RMR® footprint, but there are actually two different footprints for this sight – one licensed from Trijicon and one a workaround.

From top to bottom, the left side of figure 1 shows a Trijicon RMR next to an upside-down OEM GLOCK® MOS plate and an aftermarket C&H Precision Weapons 509T MOS plate. The GLOCK MOS supports dozens of footprints just by changing the plate. Note the raised metal down the center of the slide cut and the small boss at the ejection port side of the cut (red arrow) which keeps the plate in place. Now, look at the slide on the right side. The machinist didn’t leave recoil bosses, but cut the slide flat. When mounted, the RDS has approximately 1/16th of an inch movement in the pocket side to side and will likely come off in use.

The aftermarket slide in the middle has flush cut screw holes and four machined bosses to hold the optic in place. Which optic? That’s a good question and this Web site can help you figure that out. This slide is cut for the Docter/Noblex standard and is compatible with a Vortex Viper®.

At the bottom is a “ZEV cut” Trijicon RMR slide with a fully enclosed Holosun HE509T-RD X2 and the included mounting plate. The 509T is designed so that the optic slides onto the plate from the side and is locked into place. However, the plate is designed for the patented Trijicon footprint and not the ZEV cut footprint. In fact, the included plate won’t mount on the bottom slide because the screw hole bosses are too big for the holes in the plate for the plate to be mounted. Enlarging the holes doesn’t work because, now that the plate fits flush, the optic won’t clear the screws.

At this time, many manufacturers are still using their own proprietary set of length, width, mounting holes, and bosses (an indentation or protrusion on the firearm’s slide which matches the opposite type of boss on the RDS to help hold it against the stresses of recoil). For example, the SIG ROMEO1, ROMEO1PRO and ROMEO2 were all designed to mount directly on a SIG P320 slide.

If you want to use a SIG ROMEO on a non-SIG sidearm or want to use an Aimpoint® Acro® on a P320, you need to purchase an appropriate adaptor plate which is machined to fit the supported footprint of the slide on one side and the RDS on the other, letting you mount an “unsupported” sight.

Your selection team must understand the requirements and tradeoffs needed to select a sidearm and RDS combination at the same time. And, don’t forget the appropriate holster as one may not be available for the combination you want.

Your final list of choices are chicken and egg because there will be tradeoffs for the sidearm, RDS and holster.

 2. Select a Sidearm/RDS System

One way to hone in on the right selection for your agency is to do what San Mateo County Sheriff’s Office (SMSO) Rangemaster Sergeant David Weidner did. He and his 18 member range staff attended training classes, carried and ran with deputies for a year with multiple firearms, RDS and holster systems.

He also called each manufacturer to ask about their warranty, if they cross ship replacements and where the defective unit needed to go for repairs if they don’t cross ship. Several companies told him that his RDS needed to be sent to Europe for repairs and he would be waiting several months for it to come back.

Other important features are reticle type, size and brightness setting; battery life/auto-off/shake awake; if the sight needs to be removed and re-zeroed to replace the battery; window size; and parallax/cowitness.

In the end, the SO settled on three finalists. Remember that chicken and the egg? They did come home to roost. Sgt. Weidner called the three finalists and asked how quickly each manufacturer could equip his range staff and the first wave of deputies. Without naming names, one choice was a year out while another was six months. However, one vendor was ready to ship firearms, RDS and holsters within ten days.

Many operators like their RDS cowitnessed with their iron sight. When the RDS and sights are cowitnessed, they are aligned with each other. If the RDS fails, the iron sight can be used as a backup, along with several other methods.

As you move backwards or forwards from the distance where the RDS was zeroed, your sidearm won’t shoot true to zero. There are two reasons for that. One is the parallax due to the difference in height of the RDS over the bore of the barrel and the second is the trajectory of the bullet which only comes into play at longer distances. Instinctive holdover and aiming with a failed RDS are both parts of RDS training.

If you must remove your optic to replace the battery in a pinch and cannot get to the range, you may get it close to re-zeroed using cowitnessed iron sights – if you know what you are doing.

Test Fitting

Once you have selected the combination of sidearm, RDS and mounting plate (if required), the next step is to test fit everything together as a single unit, then properly secure them into place. I have seen more than one RDS come loose and lose zero, fly over a shooter, fly downrange, or bounce off a shooter’s forehead, then fly downrange.

The lesson learned is that your RDS, mounting plate and slide all need to have complementary mounting bosses; the correct screws need to be used; the screws and mounting holes need to be degreased; and the RDS needs to be torqued to spec using the appropriate threadlocker. Helpful hint: Never, ever use permanent threadlocker.

There are tremendous G forces acting on a slide and RDS. An ad in a past issue of The American Handgunner states that a 1911 slide develops nearly 2000 Gs when fired. Now look at those itty-bitty screws which came with your RDS and/or adaptor plate. Do you think they will stand up to 2000 Gs? No, they won’t. While the screws hold the RDS and plate down, it is the machined bosses which are taking the horizontal force as the slide reciprocates. What this means is that you cannot take a non-RDS slide and machine a flat cut and drill holes for the RDS mounting screws. Without those bosses to take the G forces, the screws will shear off no matter how much threadlocker you put on them.

And, speaking of screws, the ones which come with the sight should work, but it depends. Some RDS come with screws in different lengths and what you think is a pair of short screws and a pair of long screws may not be.

Because most slides are not symmetrical, mounting the RDS might need one of each length. An extractor channel might run to the back of the slide on one side. Install a screw which is too long and you could dig into the extractor depressor plunger causing malfunctions. If you have any questions, get answers from the manufacturer of the RDS and the adaptor plate before proceeding.

If you are using an adaptor plate like that in figure 2, you should test mount the RDS to the plate, then fit the plate to the slide to ensure that the screws won’t dig into the slide, thus warping the plate. Some slides which are designed to use adaptor plates are manufactured so that the RDS screws can extend a short distance through the plate. Check the documentation for details.

Some RDS or firearms manufacturers may recommend plates from specific manufacturers.

Check the message boards before using included plates or buying third-party plates. There is plenty of discussion about the GLOCK Modular Optical System (MOS) plates and their front to back wiggle, lack of bosses from plate to slide and minimal bosses from slide to RDS. Several companies sell aftermarket plates for GLOCK firearms which are designed to eliminate these issues.

With the screws lightly tightened, there should not be any wiggle between the plate and the slide or the plate and the RDS. If there is, try to figure out why or call the manufacturer for assistance. The purpose of the screws is to hold everything in place, not to keep things from wiggling around. That’s what a precision fit and the bosses are for.

Properly Mounting the RDS

Once you are certain that everything fits properly, it is time to mount the RDS. Along with the firearm, RDS and possibly a plate, you need a torque wrench and the specs for every screw you will be working with. The two traditional torque wrenches on the far right side of figure 2 might be great for working on cars, motorcycles and perhaps AR rifles, but they are not well-suited for working on pistol sights.

Pictured top to bottom to the left of the large torque wrenches are precision torque screwdrivers from Borka® ToolsFix It Sticks and Capri. Before buying a torque wrench, determine the torque range you will need by looking at the firearm, plate and RDS torque specs. Most are included in the manufacturer’s documentation or on their Web site.

Follow the manufacturer’s instructions carefully for the order of assembly and torque. If an adaptor plate is used, most of the time, the plate will be mounted to the slide first, then the RDS will mount to the plate.

Ensure that all screws and mounting holes are degreased. Even if the screws already have threadlocker on them, add a small drop of Loctite® Blue (recommended) or equivalent. Whatever threadlocker you use, do not use more than a drop as it might leak into the slide’s internals, causing malfunctions.

If you need to remove the RDS for any reason, such as to replace the battery or to check the adaptor plate screws, best practice is to use new screws, as the old ones have been stressed and can break off if stressed again. The manufacturers JagerWerks and C&H Precision Weapon Systems are some options.

At the beginning of every shift, check that the RDS window is not cracked and that the RDS illuminates and the screws have not loosened. Any of these failures should mean a trip to the armorer. While an officer could go on shift with an inoperative dot in a pinch, they risk injury if the screws have loosened (see figure 3). If this happens, the firearm should not be used until it is repaired.

At the beginning or end of shift, the optic window should be cleaned with a high quality lens cleaner and cloth. The emitter and hard to reach areas of the window can be cleaned with a cotton swab and lens cleaner.

Sighting in an RDS

There are three parts to sighting an RDS. First, what distance to use for zero; proper trigger control when sighting in; and, finally, the actual sighting in. After testing with 115-, 124- and 147-grain ammo, the SMSO chose a 15 yard zero as the best for holdover purposes.

From a kneeling position using hands and arms for support on a barrel (figure 4), three touching shots are taken before adjusting the sight. After each adjustment, a new aiming point is used to take another three shots until the firearm is sighted.

Why is proper trigger control required when sighting in? After running their RDS Transition Class a few times, range staff noticed that students had problems getting small groups even with untimed fire (figure 4, second from bottom right). Unless a shooter can get touching shots at 15 yards, they cannot properly sight their firearm. After spending time on trigger control, groups improved (figure 5, bottom far right). After this experience, trigger control exercises were moved before the sighting exercise.

How can you learn proper trigger control without a sighted firearm? Use the same point of aim and strive for repeatability over hitting the ten ring. That is, grouping is more important than where you hit the target. After your firearm is sighted and you practice aim and holdover, your small group will be exactly where you want it.

3. Training – Train the Trainers (2)

The last step is RDS Transition Training. There are three populations which need to be trained; range staff, sworn staff and new recruits.

The most important skills for competent shooters transitioning to RDS are to ignore their irons, find the dot immediately on punch out and focus on the threat. Many shooters try to align the dot with their irons before taking a shot or will focus on the dot as if it was their front sight. One of the biggest advantages of an RDS is that the suspect is the front sight. Therefore, you don’t need to take your eyes off the suspect.

SMSO learned that the best way to prevent students from focusing on the dot is to occlude the front of the optic with blue painter’s tape. The dominant eye sees the dot; the nondominant eye sees the target; and the brain does the rest by fusing the images.

It is important that your range staff take their training from competent instructors respected in the industry. Once bad habits are learned, it is hard to unlearn them. After taking dozens of classes, teaching their best shooters and comparing notes, SMSO took the best of the best and developed their own curriculum, tweaking it along the way.


Moving your agency to RDS is a lot more than handing RDS equipped sidearms to sworn staff or allowing them to use the RDS of their choice. It is a process with well-defined steps and checkpoints.

It took San Mateo County well over a year just to determine what they wanted to implement and, a year after that, they still are improving their training process with every class.

Without appropriate tools and training, you could be putting sworn staff in danger and opening your agency and jurisdiction to liability. An officer “fishing” for the dot or trying to aim with broken glass without proper training is a danger to himself and the community. An improperly mounted RDS which loses zero or goes downrange also presents a problem.

But, by following the steps outlined here, you will be on your way to developing and implementing a successful RDS program at your agency.           

Stay safe!

Ron LaPedis is an NRA certified Chief Range Safety Officer; NRA, USCCA and California DOJ certified instructor; is a uniformed first responder; and frequently writes and speaks on law enforcement, business continuity, cybersecurity, physical security, and public/private partnerships.

Note: Images 1-4 referenced in this article can be found within the online edition of Police and Security News (May/June 2023), or downloaded via the archive section at