Hi. I want to ask some questions about electronic sights on handguns. I have a specific application in mind for a dot sight and I'm wondering if anyone has any advice.
I've made an impulse purchase, which I hope I won't regret, of a Keltec P17. While I was reading up on them I found a guy who makes CNC milled aluminum optic plates for them. There are two great big screws on top of the slide in front of the rear sight. Apparently they hold a conventional-slide-shaped plastic shroud over the actual steel bolt. You take those screws out, you put on the optic plate, you put threadlocker on the screws, you screw the plate down on the slide. Then you can put your optic on it.
The guy makes them in a bunch of patterns and styles. I went with RMSc because everyone agrees that optics made to fit other mounting patterns tend to be much heavier. Additionally, given the difference in footprint size and what I am assuming about the thickness of the metal based on what he told me about the RMSc plate, the C-More mount plate he sells probably doesn't weigh much less than 14g all by itself. I base this on looking up the standard optic footprint size and pretending his adapters are flat rectangular prisms of aluminum 3mm thick, and rounding down to the nearest half gram. That sounds dumb but it got me a guess of 9g for the RMSc plate while I was waiting to hear back from him.
Anyway, In my research I saw some threads on Le Plebbit where guys were talking about 3D printed optic plates for the P17, some weighing about three grams. A guy had tried a few different patterns of them with different optics on his P17. With one combination--I don't recall the particulars but I looked up the specs and I did the math--with that plate and an optic whose manufacturer said it weighed 30g, the gun ran fine, at least with the ammo he was using that day. He tried a different pattern plate and put a Holosun on it that was a big fat chonky boi of an optic, weighing 42.5g by itself. 45.5 grams of mass total added to the slide, and no, I don't know if he counted the mass of the screws and battery, resulted, he said, in somewhat less reliable functioning and some apparent ammo sensitivity. Maybe. "Or maybe I should have cleaned it and oiled it before that test. It was really dirty that day. I dno, lol." Another guy said that on his own P17, an optic-and-mount combination weighing 37g seemed to cause some functioning problems, maybe, or maybe the gun was dirty, or maybe it was low quality ammo, or maybe there's some burr on the internals making something important inside that one drag, and so on. It isn't much to work with but this is where I am.
And yes, I know, Kel-Tec sells a version of the P17 that has an optic already installed, either a Viridian RFX11 or a Crimson Trace CTS1550. They come with an RMSc pattern mount already attached and the front portion of the slide skellingtonized (spoopy!) to reduce weight, compensating for the added mass of the sight. But I'm compelled to tinker with stuff. Where's the fun in that? Where's the fun in this if I don't get to dremel some lightening grooves inside the top of the slide to make it run? Also it doesn't have a rear sight, probably to save weight, and I might in the future want to remove the dot and take it to the range without it.
I promise, I'm getting to a point.
I emailed the guy who makes the CNC machined plates and he was kind enough to weigh one for me. He said the RMSc one weighs 8.7 grams. 34 minus 8.7 equals 24.3 grams, which I am taking as the probable upper bound on mass where I have a reasonable expectation of proper function. I know there are a lot more choices in RMR pattern optics, and there will be a lot more features, but RMR optics tend to be pretty heavy, and for this I need something light.
There was a guy on Reddit who had a spreadsheet of RMSc optics you could download from his Google Drive account and I started from there, but, you know, a lot of manufacturers don't have very complete lists of specs on their web pages. Some of them have no specs at all beyond what mount footprint it fits and the rest of the product page is a pep talk about how amazing it is. For that matter, I found more than one dot sight available to buy on Amazon whose manufacturer doesn't list it on their web page at all.
All that is preface.
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