I just added a Primary Arms 3MOA dot onto a Gen 3 Glock 17 build I did. I have another dot on a Ruger MkIV, so this is my first time using a dot on a center fire. I went with one that got good reviews, but didn’t cost a ton, in case I hated it. It’s a Holosun 507c footprint design, so it fit onto my slide and screwed down easily.
I did have to pop the Tru Glo rear sight off, it was too long to fit with the dot. I put an OEM rear I the dovetail. It doesn’t let me co-witness, but it fills the slot and does have the white outline for some rear sight reference if the dot croaks.
My first shots at 7 yards with Blazer 124 gr fmj were close, being centered but low. Just a few partial turns of the adjustment screw brought them high, and a bit back on the screw and few more shots brought them to the X on a B-27. At 10yds, four Fioccji 115 gr fmj stayed in the head so I think am pretty good there. I went out to 15 and all stayed in the 10 on another target.
I did notice a couple of things that I will need to work on as I get more familiar with these tools:
It took me a bit of time to find the dot in the screen. I’ve shot a pickup load of ammo through guns with open sights, so the couple hundred rounds I have shot through my two dot-equipped pistols will require more practice to make it second nature. (As expected

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I was shooting both eyes open the whole time, which isn’t easy to do when shooting for a red X ring at 15 yards. (Outside of ten I am usually a one-eyed shooter. Inside of ten, especially at speed, it’s two eyes open.) The dot easily kept the shots in the 3” ten ring on the B-27, and that is pretty darn cool.
When first bringing the gun up the dot often was high in the window, so I had to tilt the gun down just a bit to get it into play. I have this same “tilted grip” feeling when shooting the MkIV, so this is a grip/hold adjustment that I will need to make. I can see where a quick draw/close encounter situation could make someone spend time searching for the dot.
Regarding this issue; For me, I spent decades drawing and firing within 5 yards not even looking at the sights, and at 1/3/5 yards not even bringing the gun up to see the sights until shots were fired on target and I backed away to give space and assess, engage others, etc. Having a dot would not affect me in these circumstances, others need to determine their abilities/needs themselves.
I will be adding one to my Glock 43X MOS. I feel yesterday’s experience with the G-17 has let me know that I can shoot better with the dot at distance, and in close it is as good or better than with open sights. At 56 my vision isn’t close to being what it was, and I don’t think it will improve over time. I seriously feel the dot will give me an edge at the outer edges of potential engagement distances while not hampering anything with my draw/firing ability sub-15’.
As always, YMMV.
Stay safe.