So yesterday I got a reply from Holosun concerning the screws that came with my new optic. They asked me to describe the screws I required, which was a stumper: If I could technically describe the screws I have, I could solve the problem myself. I could measure them, and did, and sent photos of one of the screws in a digital caliper. My hope was that they could look up what screws were required to attach one of their optics to an Arex adapter plate. No surprise – and no real kick against Holosun that it was a vain hope. They replied to my reply that if I could tell them what I want, they would be happy to ship me some without charge. Which – okay, fair enough but no real help.
Step two: Get proactive about locating a local gunsmith. I took the advice of a commenter below and did a search for “Arizona FFL Directory” and there is one listing for the crappy little town nearest where I live. I will call that number and if the FFL is still in business – doubtful but possible – he/she/they/zer will likely know if there’s someone who can help me.
Once in the past I located an alleged gunsmith in the big town about 50 miles away and actually went there to meet him. He was so flaky about making contact I declined to leave my only carry gun with him and just learned to fix it myself. Or live with the defect – in honesty this was so long ago I don’t even remember what the problem was. But that was it as far as people claiming to be gunsmiths were back then, and so I’m not really getting my hopes up now. But we shall see.
I’m not really a gun person, so I’m trying to understand why this is hard. To get a given bolt you need to specify the length, the size/thread, and the type head. The hardest of those three to determine might be the size/thread. So if you have access to a decent hardware store, just take the plate in to determine what threads fit. And then tell Holosun what you need.
According to Arex, this is all you need – https://www.arex-store.si/product-page/holosun-509t-adapter-plate See “OEM screws from the OR plates are compatible with this adapter plate”
Oh my god, Andy, thanks for seeing that! That’s a better solution all around.
So which Holosun do you have? You might have already said but I missed it. Just got the Holosun for my p320 and used two of the screws it came with. T15 torx bit and they are on the gun. Now a range trip to dial it in.
Holosun has been pretty good to me over all and I think they will be my go to for a while.
Paul B: It’s a 509T.
If you contact the gun manufacturer, their support can probably tell you what screws are needed for that weapon.
Or the manufacturer of the original optic…
Was the gun sold with the optic?
Anyway. Failing that if you have a digital calipers you should be able to determine the screw. (Probably metric…)
Failing that, a machine shop might at least be able to help you identify the screw diameter/thread… They will have the micrometers and thread gauges
The manufacturer of the firearm can tell you that stuff if it was milled at the factory…
Did a little looking. Looks like the 508t mounts to one of the plates the Arex comes with. The plate to the slide then the red dot to the plate. The screws that came with the 508t should be used to mount the plate and the screws in the plate on the pistol should go to mount the new plate.
Depends on how much in the box stuff you got I guess.
Surely the shipping will cost more than an assortment of plausibly correct screws from McMaster Carr.
After more than 20 years in IT, I had about 2 quarts of tiny machine screws in every size ever made.
Next time, maybe try a computer (or phone?) repair shop?
(I didn’t remove the screws before giving someone’s computer back to them, although I agree it would have been funny. Back when CPU speed advanced every few months I did a lot of repair and disposal work.)
I doubt your little town has an Ace anymore, but the one 30 miles south with the nice hardware/gun store/general store etc. surely can help match the screw if you have one that fits. I think there is an Ace down there, too?
Take the plate and any screw that fits – or if you are comfortable take the gun and all. (I’ve carried in the general store when I go.) I have had surprising luck with oddball screws/fasteners at local Ace in N Tucson – I actually quit badmouthing them after 20+ years of doing so. They had all the thread gauges, etc. needed.
They take it as a challenge to ID the threads, head shape, finish, etc. and have ordered some for me, and in another case came up with the size/pitch/head answer and just recommended I try Midway (or whoever) for a quicker response and cheaper response. My youngest had a similar issue and they just gave him the one oddball screw he needed for something.
YMMV, but if you can catch a ride south it would be worth a try. And nope, never worked for them, never owned stock, etc.