Brownells’ RMR Cut Slide for Glock 19 GEN 3 – Review

Looking for reliable components to complete a build? Trying to find the most budget-friendly route to end up with a Trijicon RMR on a Glock? Well, you are not alone. These are the exact questions I was asking myself just over three years ago when trying to price out a red dot-equipped pistol.

Living on a college budget, while also being very frugal in general, had me scouring the internet to see how to get the best bang for my buck. My criteria were the following three things: a Glock platform with a threaded barrel and an RMR mounted to it.

I looked into buying a factory G19 and getting it milled, but after pricing components back in 2018, it ended up being cheaper to build out a Polymer80 and just buy the RMR cut slide from Brownells (now $239.99) and a new threaded barrel than it would have been to get all the custom work done.

At the time, the Brownells slide was just about the cheapest RMR-ready slide on the market. I also decided to get the + Window version that came with a groove cut out of the top middle of the slide to help reduce weight and give it that Gucci look.

A Brownells’ RMR cut slide mounted to a Polymer80 lower.

Using the Brownells RMR cut slide for over three years now, and shooting around 4,000 rounds between 115gr, 124gr, 147gr, and 158gr 9mm I feel like I can give a pretty good overview of how it performs.

First and foremost, I have had many issues with the Polymer80 lower, but none seem to be slide-related. While most of this use was in the configuration seen in the picture above, when encountering issues I have used the Brownells slide on OEM Glock frames, and used OEM slides on this Polymer80 to help diagnose what was causing the issues.

SEE ALSO: A Build for Beginners – Polymer80 Step-By-Step

Every time I was having cycling issues with this Polymer80, I would swap my Brownells slide for an OEM one which didn’t fix the issues. Also, whenever I used the Brownells slide on an OEM frame it ran flawlessly. The moral of the story is that Polymer80’s are hit and miss, and it took about a thousand rounds and racking the slide by hand up to ten thousand times to get it running pretty well.

Low-profile RMR cut on the frame of the Brownells’ slide.

The RMR cut sits way lower into the slide than I was expecting, which is a great feature. The slide cut is as deep as the front of the RMR frame, so the glass sits flush with the slide. This allows the height over bore to be lower than other MOS models, most OEM slides milled by aftermarket companies and mounting options such as the GLS frame mount.

Maintaining a lower height over bore creates a lower moment of inertia when firing, which in turn reduces recoil. Due to the lightweight nature of the RMR, this reduction in recoil is not as noticeable as it would’ve been if I was using a heavier red dot, e.g. an Aimpoint ACRO, but I’ll take every mechanical advantage I can get.

When I went to install my RMR I was also impressed with the tolerances of the frame cut. The RMR popped in nice and snug, and I bet I could’ve even squeezed off a few rounds without fastening down the retaining screws and it would’ve stayed in place. But I know better.

Fastened down though, the RMR stayed rock solid for three and a half years before I had to remove it and change the batteries. I never noticed a shift of my point of impact, nor did the retaining screws ever back out during the 3,500 or so rounds I put through the pistol.

This Brownells G19 slide milled for an RMR has been the perfect host. As for reliability, fit, function, and aesthetics, I couldn’t be happier.

Top: Brownells Gen 3 G19 Slide, Bottom: Glock OEM Gen 4 G19 Slide

To help with manipulating the slide, Brownells added their own pattern of serrations to this slide. The rear set spans a slightly further distance along the length of the slide than the slide serrations of a Gen 4 OEM Glock 19. This gives a slightly more textured surface area to grab onto.

The front serrations are a nice touch as well. They look cool, are useful if you are into press checking by pulling on the front of the slide (I press check with the rear), and ever so slightly reduce the overall weight of the slide. If features add style points while producing benefits to the platform, we all know that’s a win.

Window Cut Along Top of the Brownells Slide

While probably being the most Gucci feature of this slide, the window cut also removes a decent chunk of 17-4 stainless steel that the slide is machined from. Along with showcasing any fancy barrels you may be running, you get the benefits of a lighter slide and quicker cooling off your barrel.

As for reliability, I have never had something fall into the port while firing that has impeded its operation or cycling. However, while unlikely, it is possible to get a rock or piece of brass wedged between the barrel and the frame. Brownells offers this slide with or without the top window cut so you can go either route.

As for me, I am happy with my choice of the window version. It has a good recoil impulse and is well-balanced overall.

Left: chamfers for Brownells slide. Right: Glock OEM Gen 4 corner rounds.

One difference between the OEM slide and the Brownells is the corner rounds. The Brownells slide is just more “blocky” than the original Glock slide. Instead of smooth edge rounds for the corners of the slide, Brownells uses chamfers.

These are basically just a 45 degree cut to remove sharp edges and maintain a shape similar to the OEM specs. From a manufacturing standpoint, chamfers make sense and are cheaper to produce.

With the very competitive price they have these slides selling at, it looks like they passed that saving right on to the customer, which as I buyer I appreciated.

Overall, I have been very happy with this Brownells Gen 3 Glock 19 slide with the RMR cut and top window. I haven’t caught any cycling issues caused by the slide itself, and it has performed flawlessly over the last couple of years.

Tolerances seem to have been held tight, and I had no issues originally installing the slide parts kit. While looking slightly “blocky,” it makes up for it with the Gucci top window and front serrations. This slide has all the features I needed at a great price point.

For more information show the RMR cut slide at Brownells.

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About the author: Mitchell Graf is passionate about hunting and competition shooting. During college he was the shooting instructor for Oklahoma State’s Practical Shooting Team, and these days he spends as much time as he can chasing after pigs and coyotes with night vision and thermals. You can follow Mitchell’s adventures over at his Instagram @That_Gun_Guy_

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