Chad Wallace

July 28, 2025

Gear, Optics, Review

Primary Arms SLx RS-10R

Chad Wallace

July 28, 2025

Gear, Optics, Review

Primary Arms

SLx RS-10R Review

Primary Arms has come out with their new SLx RS-10R. This is an updated version of the original RS-10 reflex style red dot. One of the big complaints about the original was the mounting footprint it used. Well, the SLx RS-10R has fixed that issue.

As with the original, the SLx RS-10R is packed with features. More important than all of those is the “R” designation at the end of the model number. That “R” stands for RMR. I don't think Primary Arms can say it, but we can. What that means for you is that the RS-10R now uses a RMR footprint. Or a Holosun 407C/507C footprint since they are essentially the same. The only drawback to using the RMR footprint is that the RS-10R now uses the smaller cr1632 battery instead of a cr2032. But through some magic, you still get 25k-50k hours of battery life.

Now back to the rest of the specifications. The RS-10R runs a 3 moa dot. I find the dot size to be a good compromise, no matter if you mount it on a pistol or rifle. It has 11 brightness settings. Of which, the bottom 2 are night vision compatible. To adjust the brightness, the RS-10R has soft touch buttons on the left side. When you reach the highest brightness setting, the dot will flash so you know when the limit has been reached. You also don't have to worry about turning the RS-10R on or off. It uses Primary Arms’ “Autolive” technology. This tech automatically turns the optic off when it is stationary and then on when it senses movement. Worth noting is the RS-10R has 1 moa click adjustments that uses a flathead to adjust. One can even use the rim of a spent case to adjust it, which I have done before. No trying to find the correct allen wrench. These clicks are tiny, but way better than no clicks at all.

Window size in these small red dots can be hard to understand sometimes. Manufactures spec the window size out, but it doesn't take into account if it is rounded or squared. Or where it is rounded and squared. I recommended looking through them to see if you like the window shape. Even though the RS-10R doesn't have a huge window, it is very well shaped to pick up the dot easily. Primary Arms specifies it as 23x19mm. I really like the shape. It is easy for me to see. Other people who I asked about it said the same thing, it's easy to find the dot. Primary Arms also fixed the refresh problem on the RS-10R. The original RS-10 would “galaxy” out because the refresh rate was too slow. The RS-10R does not have this problem. The dot stays consistent when moved and doesn't flash.

The SLx RS-10R uses an aluminum housing. They use 7075 aluminum which is a little stronger than the commonly used 6061. I like how the housing sticks out farther than the lens, giving it a little more protection from drops. One drawback to the RS-10R's construction is the higher deck height of the mounting surface. It sits higher up than some red dots. This doesn't hurt anything, but you do notice it when installing taller iron sights.

I ended up mounting the RS-10R on the Fusion XF-Pro. The XF-Pro uses a mounting plate system. This leads to you noticing the RS-10R’s deck height even more. It didn’t bother anything and I can pick up the dot easily. The dot on the RS-10R is pretty clear, even with my astigmatism. What I really like about the RS-10R, besides being an RMR footprint, is the window. For some reason I just pick the dot up quickly with the way the window is shaped. I am glad Primary Arms updated the RS-10 to an RMR footprint and fixed the refresh problems. It performs great.

I know there are a million reflex pistol red dots on the market now, but the Primary Arms SLx RS-10R is a great option. You get a lifetime warranty. It has a side-loading battery with their “Autolive” on/off function. Plus it now features that RMR footprint everyone was asking for. If you are in the market for a pistol red dot, definitely go check out the new SLx RS-10R.

Firearms Insider Reviews - Key Points

Claim to Fame:

RMR footprint red dot

Target Market:

Anyone wanting a pistol style red dot with a RMR footprint

Features, Benefits, and Specifications of this product:

Battery Life: 25,001 - 50,000 Hours
Battery TypeCR1632 3V Lithium Coin
Side-loading CR1632 battery
Click Value: 1 MOA
Open Emitter
Finish: Hardcoat Anodized
7075 Aluminum construction
Mount Compatibility: Holosun 407C/507C, RMR
Night Vision Compatible
11 Brightness settings
23 x 19mm window
3 MOA Dot
Lifetime Warranty
Weight: 1.1 oz.

What other aesthetic options or finishes are available?

Original SLx RS-10

What others are saying?:

Nothing found as of publishing

Link to other reviews:

Beyond Seclusion on YouTube

Price point:

MSRP = $209.00

Retail = Same

I need it now! Availability:

Primary Arms, Midway USA, or your local gun store

Our Rating:

Pros:

RMR / Holosun 507c footprint
Click adjustments
Side loading battery
Autolive
Lifetime warranty

Cons:

Deck height

Score: 8.50 Great

Favorite Link: Fusion XF-Pro Review

Chad Wallace

April 2, 2023

Review

Primary Arms SLx MD-25 gen 2 red dot

Chad Wallace

April 2, 2023

Review

Primary Arms has updated their SLx MD-25 red dot optic to a Gen 2. The Gen 2 gives you all the great stuff as the first generation, but it now includes Primary Arms’ AutoLIve. With the added AutoLive function, this makes a great red dot for either a rifle or carbine. There are two versions available, one with just a red dot, or one with an ACSS reticle. I received the ACSS version, so everything here will be on the MD-25 Gen 2 with the ACSS CQB reticle. Most of the specifications, except the reticle, apply to the dot only version of the MD-25 Gen 2 also.

Let’s start this out with an AutoLive explanation. The AutoLive function, of the MD-25 Gen 2, automatically turns the red dot “On” when you pick up or move the optic. It also turns the optic into a sleep, or “Off” mode, after a few minutes of no movement. A big advantage to an auto-on reticle/dot is that it is ready when you need it to be. The AutoLive also extends the battery life, since your optic isn’t “on” all the time. Whatever setting the brightness dial is set to, is the brightness that it turns on at. No readjusting necessary. I absolutely love the AutoLive function. Speaking of brightness, the MD-25 Gen 2 has 11 adjustments on a dial. From night vision compatible all the way up to super bright. The 2032 battery is also housed in the brightness dial. Primary Arms specs the battery life at 12000 hours on the medium setting, so 5 or 6 on the dial. Battery life might seem a little low to some people, but there is more information in the ACSS reticle. For comparison, the MD-25 Gen 2 dot only version has a 50000 hour battery life.

This particular MD-25 Gen 2 has the ACSS CQB reticle. If you don’t know anything about the Primary Arms ACSS reticles, they are usually a horseshoe line around some sort of chevron (think triangle). The horseshoe on the Gen 2 measures 65 MOA. The chevron triangle sits inside the horseshoe and is used as your main aiming spot. For close up work, just cover the target with the chevron. For more precise work, use the top point of the chevron. The ACSS CQB then has three dots below the chevron. These dot’s are for ranging, as is the bottom of the chevron. The reticle can work with a few different common caliber options as seen in the photo. I like the ACSS CQB reticle, but it is pretty small, so it can be difficult to make out the aiming points for different ranges. The MD-25 Gen 2 is still a red dot style optic. So this means that the image is projected onto the viewing surface. It is not an etched reticle like a scope. This really only affects you if you have an astigmatism, which I do. So for me, the chevron “starbursts” out and looks more like a dot. This is just something to take into consideration. If you have decent vision, the reticle will be very clear. For my use, the MD-25 Gen 2 is not a long range optic, so this doesn’t bother me at all. When shooting real close targets, an advantage to the ACSS CQB reticle is that you can figure out how far above a target you need to aim, to compensate for mechanical offset. Those dots below the chevron, as well as the 65 MOA horseshoe, also help for aiming at those close targets. You don’t have this option with a standard dot only reticle, which is why I feel the ACSS CQB is a better reticle option for an AR rifle.

The Gen 2 MD-25 is not one of those super tiny red dot optics. I’d say it is medium size. Not so small that it’s hard to see through, and not so large that it’s a tank sitting on your picatinny rail. It only measures 3” long, so almost half the length of those expensive “red dots”. The MD-25 uses 25 mm lenses, but the field of view is really good. Primary Arms says it rivals 30 mm red dots, and I believe it after looking through the MD-25. Even though the MD-25 isn’t a small red dot, it still only tips the scales at 6.5 ounces. It also comes with different mounting height options. So no matter what you put it on, you can get the sight right up to your eye level. If for some reason you don’t like the supplied mount, the MD-25 can be mounted on standard T1 And T2 micro mounts.

I’ve been really impressed with the MD-25 Gen 2. It is built super strong. I’m not sure I could break it if I tried. Even if I was to, it’s covered by Primary Arms’ lifetime warranty. The little capped turrets even have raised nubs to keep them protected. These protection nubs will also keep stuff from snagging on the turrets, or at least help. The little turret caps also are aggressively textured with an adjustment built into them for making sight adjustments. The mount is also super strong. Once clamped down, the MD-25 isn’t going anywhere. I wouldn’t hesitate to put this on a rifle that gets beat around some.

If you are looking for a rugged red dot, that’s not a dot, look into the Primary Arms MD-25 Gen 2 ACSS. This thing is a great size for almost any rifle. It has a ranging type ACSS reticle that even works with a .22 lr. The AutoLive gives you plenty of battery life, over a years worth, and it makes the optic “always ready”. Go check out the SLx MD-25 Gen 2 over at Primary Arms, It’s a good red dot style sight with a unique reticle.

Firearms Insider Reviews - 8 Key Points

Claim to Fame:

Larger window red dot

Target Market:

Those wanting an auto on/off red dot with a ranging reticle

FNBs (Features & Benefits of this product):

AutoLive functionality
Wide field of view
ACSS CQB reticle
Up to 12,000 hour battery life at medium setting
Uses one CR2032 battery (included)
Next generation ruggedized mounting system
Includes risers and spacers for mounting to 0.96”, 1.41”, 1.54”, or 1.64” central height
Compatible with standard micro mounts
Fully multi-coated anti-reflective lenses
12 Illumination settings, night vision compatible
3" long
Weight - 6.5 Oz.
Fog resistant
0.5 MOA adjustments
Lifetime Warranty

What other aesthetic options or finishes are available?

Dot Only version

What others are saying?:

5/5 stars on Primaryarms.com

This is my 5th or 6th scope purchase from PA. I've never been disappointed yet, so when this one was announced I quickly put it on pre-order to replace a Vortex SPARC that I've never been happy with. I bought this to go on a home defense bullpup shotgun. It is fantastic for this purpose. The big outer circle, with the small aiming dot in the middle, is perfect for fast sight acquisition, and the shake-awake feature gives you one less thing to think about in a crisis situation. The included height adjustment plates let you tailor the height of the sight to your own weapon and preferences. Just another area where PA beats the competition in quality, value, and price. With eleven brightness settings on this reticle, you see it outside in the brightest sun, all the way down to night vision compatibility. I usually prefer green illumination over red, but this sight is extremely clear and my old eyes have no problems with it. - Highly recommended.

Link to other reviews:

Lynx Defense

Price point:

MSRP = $199.99

Retail = Same, but Primary Arms runs sales quite often

I need it now! Availability:

Primary Arms

Our Rating:

Pros:

Clear
Bright, well lit, reticle
Autolive
Mounting options
Field of view due to larger physical size
65 MOA circle of ACSS reticle

Cons:

Hard to see bullet drop compensation marks
Battery life compared to Red Dot version

Score: 8.00 Great

Favorite Link: Walker Defense

Community Reviewer

June 28, 2020

Review

Swampfox Wolverine slide and Justice red dot combo

Community Reviewer

June 28, 2020

Review

Written by: Rusty Odom

This review is on the new Swampfox optic Justice 27mm red dot pistol sight and the Steel City Wolverine combo. Let me start by saying I am an average Joe shooter with a huge interest in firearms. I am always looking for the latest greatest item or something to improve on an older firearm to make me a better shooter. For this review I chose a Glock Gen 3 model 22 in .40 S&W to convert to 9mm. The firearm was purchased some years ago for around $295 and it was a local police trade in. I tossed it in the gun safe, knowing one day I’d do something like this to it.

The Swampfox Justice red dot and Steel City Wolverine slide combo. The slide is in a distressed green pattern and is available for the Glock 19 and 17 Gen 1-3 only. The slide comes with the channel liner already installed and with suppressor height fiber optic sights. They are in the combat configuration (rear sight in front of the optic), the slide is smooth with no machine marks on the outside, except in the area of the optic cutout. The threads on the mounting service were nicely tapped and debured. When mounting the optic it is a nice snug fit. It also comes with 3 sets of screws and Allen keys to mount the optic. The slide has great machining in the front for a good grasp to reload with wet or sweaty hands. It’s texture is just the right combination of aggressiveness, not to be uncomfortable when sharply grasping the gun. It has a lightning cut above the barrel, I assume to reduce weight. I have a concern of dirt or debris getting into it and causing issues in a real world situation.

The optic is clear and crisp, it has an 27mm window and is made out of 7075 aluminum. There is a Liberty version that has a smaller window of 22mm. These are duty rated and have a new and improved hood over their last model. It has a top load battery that takes the CR1632 battery. Not Chad’s favorite. It weighs 1oz without the battery, its height is 1.04”, length 1.78” and width 1.24”. It has the normal parallax free, fog proof and ruby coated lens.

It claims to have a greater battery life and new and improved shake a wake motion sensing illumination. The slide and optic are both for the RMR mounting option. Assembly of the slide is straightforward, just like your normal Glock slide would go together. A Brownells Glock completion kit was used for final assembly.

The initial sight in was done by co-witnessing the dot and the front sight post. Once the impacts were on target I did a ⅓ co-witness, raising the dot above the front sight post to declutter the sight picture. The slide had a few failures to feed, but after some lubrication and some dry fire, it ran flawlessly. The optic is easy to pick up, with some practice, for someone that is new to the red dot game. So far I have fired 350 rounds of 115 grain 9mm with no problems after the initial FTE. I was able to keep all the rounds in the 10 ring at 10 yards. Even with astigmatism the dot was clear with some adjustment of the intensity level.

In my honest opinion I do believe that this will make a great setup for someone that wants to put an optic on their Glock and doesn’t want to have their slide cut, or wants the benefits of having one frame with two different calibers. After my initial testing and what I know of some of the other optic I own from Swampfox, this appears to be a quality red dot. The slide is nice and clean, the battle worn or distressed coloring gives it some character.

Firearms Insider Reviews - 8 Key Points

Claim to Fame:

A quality optic red dot with a standard RMR footprint, with a cost half the price of others. An improved hood to protect the glass, as well as shake awake technology. It claims to be rated for law enforcement and duty use.

The slide is well textured, nice smooth and rounded corners. Assembly was simple, machining was good.

Target Market:

People who want to get into the red dot game and not have to have their original slide machines. Also those who have a .40 or .357 Sig that want to convert it to 9mm for cost reasons.