Agreed. That seems pretty far off to me.Originally Posted by Adam
Agreed. That seems pretty far off to me.
I had some business at my local sheriff's office yesterday. The senior deputy who helped me was carrying a G17 with a 507C. I also spoke with another deputy who is very happy with her 507C with green reticle. We're fairly rural here, but pistol-mounted optics are definitely gaining ground with our local LE agencies and Holosun is well represented.
Last edited by Mark D; 07-15-2021 at 03:27 PM.
I have a local SO in my area that is very rural, with only a handful of deputies- but they are running 507’s on Glock MOS 17 and 34. I also know of a very large SO in a very urban jurisdiction that are issuing Sig 320s with 507’s as well. Red dots are definitely catching on locally.
Maybe there is a difference in how Dawson and Ameriglo measure their rear sights? I just took my calipers and the deck height of my HS507c, on the FCD plate, from the bottom of the rear notch, is about 0.325" on my G19 MOS here in my hand. A GL-404 (the lowest black steel AG sells) lists at 0.394", giving me a sight that is 0.069" above the optic body (I'm assuming the notch is a bit lower, of course). The only other option(s) available on AG are taller than this. So I'm perplexed why this would be too high? But I might be missing something, that is for sure.
At any rate, I did order one, so if I messed up, thats $28 gone and I'll know more about how they measure sights.
They do. I see what Ameriglo is going for with adding the .075 depth of the dovetail to their rear sight height, but Dawson uses measurements that you can actually take accurately with a pair of calipers.
I just measured mine, Dawson measures from the top of the slide to the top of the sight, front or rear. Their system of "top of slide to bottom of optic window + .100" is the easiest to follow and accurately measure. Dawson also recommends a front sight .005" shorter than the height of the rear. I have .335 rear and .330 front for my 19/forward controls/RM06 combo. If the .315 front sight is tall enough (and I think think yours probably is) in a Dawson you'd want a .320 rear. Add Ameriglo's .075 to that and you have .395 which is basically what Ameriglo says their height is.
You could reach out to Dawson, they're quick to respond. I'd verify your info and change the order. Your call though, you'll get it worked out.
Last edited by Adam; 07-16-2021 at 07:04 PM.
Yeah I'll let it ride. A while ago I made a bit of a study of sight options when I went through this merry-go-round with my G34. I never did understand why Dawson recommends a delta of 0.010" rear/front, it didn't really add up to me, but now I understand. My frame of reference was the Glock OEM "heights" which end up with a delta of 0.080", rear to front, most of the time. This "delta" shoots to POA for me for most ammo I shoot, so I try and measure sights consistently that way.
Below is a snip from one of my option analysis spreadsheets. The GL-409 set from AG matches that delta exactly, since it consists of a 0.315 front and a 0.394 rear, hence why I picked the 0.394 rear GL-404. I also think what's playing into this is the deck height of a 507c doesn't seem to be the same deck height as an RMR.
So yeah I think I'll stick with the AG for now and see how this shakes out. Good discussion though, made me think.
Last edited by RJ; 07-16-2021 at 07:18 PM.
@RJ I'm tracking now. So you ordered an Ameriglo rear, not a Dawson rear. In that case you should be pretty dang close!
I sell Holosun (and other gun stuff) on the side of my LE job. Holosun has outsold Trijicon about 20:1. My own agency has been big on the 509T. I sell a lot to guys that work for a large SW US agency and they have been big on 507Cs and 5078Ts with quite a bit of demand for green dots.
Right, so this all got installed and checked today. tl;dr: I think for BIUS, this combo of 0.315" front/0.394 rear on a G19 MOS w HS507c/FC RMR, G plate is a little low, actually.
I can see the front and rear ok, it's just the bottom of the rear sight channel is below the deck height of the optic, when mounted. Ack, I suppose it was worth a try, as I already had the 0.315" front from a previous go around. I'll leave these on for the moment and get back to validating the gun (my EDC).
So I don't think I'm done, and I'll probably spend some time pondering whether I will change to a taller rear sight after I shoot it some in backup mode.
Picture and spreadsheet snip, fwiw, in case my process helps anyone.
Anyone have a spare Holosun 407/507 picatinny mount they'd part with? PM me if that's ok mods.
@RJ looks like that is definitely a "low-witness". I have questioned "how low can I go?" and right where you're at is the break in my comfort level too. You were otherwise pretty spot on with your guesstimates it looks like though!
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