Primary Arms SLx RS-10 Red Dot: How's It Doing Two Years Later?

— Jason MosherCADRE Dispatch

Primary Arms has been making great optics for years, and the SLx line of optics is among their best. Today, we are looking at the Primary Arms SLx RS-10, which has been out for nearly two years. Initial reviews were showing great promise, but have the expectations held up?  

When I first buy an optic, I like to perform a series of functional tests to simulate temperature extremes, water submersion, and impact. I also look at the functionality of using and programming the optic as it compares to other models available. My first impression of the RS-10 was good, and I’ve been using it on and off for nearly a year and a half now.

Primary Arms XLS RS-10 red dot.
Primary Arms XLS RS-10 red dot has a super clear lens making it easy to see while shooting. [Photo: Jason Mosher]

Regardless of the test being performed on a product, I feel that time is the ultimate test. Months and years of use will reveal any weaknesses in a product. With an optic, you have durability stressors like recoil from the gun, impact from being handled and holstered, and unfortunately, sometimes they get dropped.

So, I like to swing back around to products I’ve been using for a while and see how they are holding up. This is an optic I have continued to use on multiple firearms. After using it on my Walther PDP and Glock 45, I mounted it on a B&T. PA supplies a Picatinny rail mount, so I’ve had it on this gun for a while now.

But now I’ve moved it back to my Glock 45 for some gun range time. And to see if any issues have popped up that I didn’t notice before.

About the Primary Arms SLx RS-10 red dot

Open emitter red dots are the go-to choice for pistol-mounted sights. As these miniature sights feature only one piece of glass, they offer quick sight acquisition even for people with failing eyesight or without optimal iron sights.

Many pistol-mountable red dots are designed for hobbyists, but Primary Arms’ RS-10 stands out as being purpose-built as a duty optic. According to Primary Arms it was granted a “silver-tier rating by the National Tactical Officers Association.”

The RS-10 has 11 brightness settings, one of which is compatible with night vision gear. Plus, it’s made of 7075 aluminum construction, adding to its durable design.

The RS-10 has Auto-Live motion activation, which turns the red dot off after three minutes to preserve battery life. It will reactivate when it senses motion, making this optic a great choice for home defense. I’ve had mine turned on, using the same battery, for one and a half years and the battery is still running strong.

The RS-10 features an easy side-loading battery compartment for quick battery changes without unmounting. On average, its CR2032 batteries should run for 40,000 hours of continuous use, which is made even longer when you factor in the Auto-Live feature.

Primary Arms XLS RS-10 red dot.
The side loading tray is easy to access when changing a battery. [Photo: Jason Mosher]

Primary Arms chose to use the Docter/Noblex footprint for direct mounting to various surfaces. This isn’t my favorite footprint but it’s not hard to find adaptor plates for most guns. This model comes with an MOS plate for Glock pistols and a Picatinny rail mount, which is a nice touch.

Functionality and size of the SLx RS-10

A few things stand out right away with the Primary Arms SLx SR-10 compared to many other pistol-mounted red dots. First, are the power buttons. PA placed both the up and down buttons on the left side which I like. This makes it easy to adjust the brightness of the dot without moving your grip on the gun.

When the sun comes out or you move from indoors to outdoors (or vice versa) the dot requires adjustment. With a two-handed grip, I can reach up with the thumb of my support hand and hit either button. The only downside with this design is left-handed shooters will have a harder time adjusting the settings without changing their grip.

Primary Arms XLS RS-10 red dot.
The up and down buttons are both located on the same side for easy access while shooting. [Photo: Jason Mosher]

A second feature, which I mentioned above is the side loading compartment for the battery. I’ve never been a fan of bottom-loading batteries as it requires unmounting the optic for a battery change. A popular style right now is top-loading batteries which I like. Side-loading compartments are nothing new, but aside from Holosun, are not used as much.

A tool is required to remove the side tray, but that’s not a big deal since it doesn’t need to be changed very often. I’ve submerged the SR-10 in water before and didn’t have any issues with it getting in the battery compartment.  

You can shut the optic down completely by pressing both buttons for about two seconds. Press either button for two seconds to turn it back on. When the optic is on, the auto shut-off/on is functional.

How did it hold up over time?

As I mentioned above, I’ve mounted the Primary Arms SLx SR-10 on multiple guns over the past year and a half. It was on my B&T for about sx months, which I carry in my car or backpack frequently. I’ve also had it to the range multiple times for some fun drills with sub-gun-sized guns.

Recently, I placed it back on my Glock 45 to do some handgun training with it. PA included multiple sets of screws in the box, so it was easy to move it from the Picatinny rail back to the included Glock MOS-compatible plate.

I ran multiple drills with the RS-10 and didn’t have any issues. I was looking for any problems with it staying zeroed and to make sure the red dot was functioning correctly.

shotting glock 45 with red dot and weapon light
Regardless of the amount of light, the SLX RS-10 red dot will adjust to the setting needed. [Photo: Jason Mosher]

My Safariland 7360 RDS duty holster is one of my favorite holsters to use with the Glock 45. This holster fits “standard” size optics like the Holosun 507 so the SR-10 also fits in it perfectly.

When shooting with a pistol-mounted red dot, I always push against it to rack the slide. This does cause a little more pressure on the optic, and I’ve even broken a different brand doing this before. However, the Primary Arms SLx SR-10 performed like it was new.  

For $199 this is a bargain

You can spend hundreds of dollars more than this on plenty of other optics, and cheaper ones are also abundant. But I’m going on two years with an optic that’s been used on multiple guns and is still running on the same battery.

A side-loading battery, long battery life, and auto on/off are all great features to look for in an optic. Quality material is used in the construction of the frame and PA includes a Glock adaptor plate and Picatinny rial mount adaptor.

posterior view of red dot on glock 45
The overall frame on the PA XLS-RS-10 is smooth and compact. [Photo: Jason Mosher]

My opinion of this little red dot hasn’t changed since facing the challenge of time. This would make a great optic for home or self-defense, and I wouldn’t hesitate to use it on my duty gun, either.

I will continue to use the Primary Arms SLx SR-10 red dot and see how it holds up with more use and more time under its belt. But I am going to guess it will hold up just fine. For the quality and features, this is a bargain optic.

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