Ballistics by the inch

Reflections upon a reflex sight.

I recently came across a really good sale on a Trijicon RMR reflex sight, and decided to take the plunge and add it to my Glock 21. I had handled and shot some other competition handguns with a reflex set-up, but I hadn’t yet tried one on a more-or-less stock gun intended for routine use, and wasn’t sure how well it would work or how I would like it.

My G21 had been set up to handle the .460 Rowland cartridge, complete with compensator, so it wasn’t exactly stock. You can see it here:

Converted G21 on left, G30S on right.

As I have previously noted, I have now changed over to using the .45 Super cartridge rather than the .460 Rowland because the .45 Super offers most of the benefits of the .460 Rowland without some of the disadvantages. But I have kept the conversion kit in place because it gives me more flexibility in ammo selection and more control of the gun. And since I don’t carry the G21, the extra mass/length of the compensator doesn’t make a difference in day-to-day use. Thinking along those lines, I figured that adding a reflex sight to the G21 wouldn’t cause a problem, and might make it an even better home defense firearm.

So along with the RMR I got an adapter plate which just slides into position where the rear sight of the Glock mounts. Mounting the optic just took a few minutes and no special tools other than a light hammer and brass punch. Here’s the result:

And this morning I had a chance to take it out to the range for testing, to see what I thought of it.

I like it. A lot.

It took a little getting used to, since I have about 50 years of shooting experience which has conditioned me to always look for the front sight on a gun, and place that on the target. The RMR sticks up too much for that to work well, and if you can see the front sight through the RMR you probably won’t see the red dot. Rather, you have to tilt the front of the gun down for the red dot to appear. This actually puts the gun back to the normal position you shoot it in, but you’re just looking above the front sight — parallel to the slide, as it were.

The RMR I got was the one with the 6.5 MOA dot, which I figured would be easier and quicker to get on target even if I wasn’t wearing my glasses, and would give me adequate accuracy at any distance I was likely to use the gun (say 25 yards or less). At 10 yards distance at the range, the dot appeared to be about half-an-inch across, perhaps a bit more. For my purposes this was more than accurate enough to knock down steel plates consistently. As I get more used to the RMR, moving out to 25 yards should give similar results.

Now that I’ve tried it on this gun, I can understand why others have decided to have a mount for the RMR milled into the slide of their gun. That would bring down the location of the dot and make everything more consistent with previous shooting experience. It would also make the gun more compact and more suitable for either duty or concealed carry. I doubt that I will go to the trouble or expense to have this done on the G21, but it is something I would consider for the G30S shown above, particularly if the next generation of reflex sights are even more compact and suitable for a handgun. It’s something to think about, anyway.


Jim Downey


September 27, 2017 Posted by | .45 ACP, .45 Super, .450 SMC, .460 Rowland | , , , , , , , , , , , , , , , , , , , , , | 1 Comment