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  • Writer's pictureGary Anderson

I Tested The Primary Arms GLx RS-15 Mini Reflex Sight

I test and review firearm optics for a living, so you can trust me when I say that this Primary Arms red dot performs flawlessly. Here’s my hands-on review.

primary arms glx rs15 red dot review

FYI, prices and ratings are accurate as of time of writing.

Primary Arms - GLx RS-15 Mini Reflex Sight

primary arms glx rs15 red dot review

Highlight: Built to handle anything that is thrown at it.

Helpful review: I just got this new mini reflex sight from one of the best manufacturers, the Primary Arms GLx RS-15 red dot. The GLx was made on its first day to fit on a large-frame pistol slide. I am talking about the Glock 21 here. Currently, I am milling out the slide to mount the GLx on a Gen 1 Glock 21. If you are familiar with this original Glock pistol, you know this beast is like shooting a cinder block. The grip or frame is large, as the SF or short frame came along at Gen 3, if I remember correctly. The SF model grip frame means "Short Frame," which makes the pistol easier to hold onto; unless you are built like me with bear paw-sized hands, it's great for us.
My long-term plan for the Primary Arms GLx is to mount it on a Gen 3 Glock 17 fitted with high-rise sights to accommodate a suppressor. Until that happens, I will fine-tune the milling machine, cut the slide to receive the GLx, and then replace that with an optic cover plate. The Glock 21 is my favorite qualification gun. The gun and I have been around for a long time, and it would feel weird not to keep it close to the original.
Let's get into the specifics of the Primary Arms GLx optic. The body of the red dot is made from aircraft aluminum and weighs next to nothing. The optic size is relatively nil; I think it sits only one inch higher than the top of the slide after the milling. The glass in the red dot is crystal clear and easy to see through. The brightness adjustments are easy to use, with two buttons, one for up and one for down, so it does not get simpler. The brightness adjustment also includes settings for Night Vision. This red dot optic is ready to go for any pistol use. This optic is not set up for use on an AR or other rife or carbine platform. The kit comes with the mounts for a relief cut into the slide and nothing in the way of picatinny mounting.
The reticle is adjustable by a flathead screwdriver. The optic comes with everything needed to screw this to your gun; save the LocTight; you will want to ensure this red dot does not shake loose with recoil. The LED is powered by a simple flat battery, the CR2032, and they send two batteries in case you use one for 20000 claimed hours; you have a spare in hand.
The article is on the strange side, for me, at least. The reticle can be the Vulcan-style Big rings around a tiny dot, or turn the Vulcan reticle off and use the small bright red dot alone. The purpose of the Vulcan reticle is to show the shooter that they are off-center of the target. If the shooter can see the outer ring, the gun is off-center. If I point the gun perfectly, I can not see the ring, just the red dot. I'm not too fond of this approach for the Vulcan reticle. If the manufacturer provides an outer ring and the red dot, I want to use both of them, as I find on other red dots. The preference is my opinion; if you think this red dot is for you, do not hesitate to pick one out for your pistol.
Finally, this one can change the battery and not remove the sight from the slide on the compact red dot optics made for pistols, especially relief cut for optics. Other makers have the battery door on the bottom of the sight, and the optic has to be removed. The battery must be changed, and then the sight in the gun must be changed again. Other optics will have the battery door on the side of the optic, which is very convenient, and it gets pretty bulky and, in my opinion, kind of a space gun-looking setup. The Primary Arms GLx has the battery door right on the top, is easy to get to, and screws down water-tight with the provided tool. — Gary Anderson

Get it from Amazon now: $299.99 & FREE Returns

primary arms glx rs15 red dot review


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