Red dot screw part numbers and ordering info

[dfeder530]

Sorry if this has been gone over before, but for the dumb guy in the room, I want to order replacement screws from McMaster.
What sizes do I need?
Glock 19 Gen 5 with CH plate, Holosun 507C
-Plate to gun screw size/part#?
-Holosun to plate size/part#?
Glock 17 gen5 with Leupold DPP pro MOS plate
-MOS plate to gun size/part#?
-Leupold DDP to plate size/part#?

Thanks to all, still learning ref MRDS and trying to build up my spare parts bin.

Steve

I can say with certainty that the screws that attach a plate to the MOS slide is a M3x0.5mm 6mm in length. The ones I use have a tensile breaking strength of 140,000 PSI. These screws I believe are also the same that bigtexoutdoors.com sells as MOS screw replacements. This is the exact screw number you can buy on McMaster-Carr: 94414A712

[D-der]

i spoke w Holosun and they said the screw is 6-32 x 7.5mm, slightly shorter than 5/16 (this is the shorter proprietary screw with a narrow head). They’re in the process of making them available for order on their website. I was able to buy a bag of 50 for $17.50. They had to go with the narrower head to make room for the electronics in the newer versions of their sights. Holosun has excellent customer service, offering to send extra screws free, just need a pic of the sight’s serial no., but I needed a larger qty. I spoke with kelviny@holosun.com through their customer service contact.

Thanks very much, appreciate the information.
I've also found Holosun's customer service to be very good,
perhaps the gentleman I exchanged email with wasn't aware,
I'll try this contact first of the week.

[SoCalDep]

FYI the McMaster 6-32 5/16 alloy steel screws don’t fit flush with a Holosun 507c. The head has the proper angle but sits proud of the countersink as it doesn’t have as sharp a head edge as the stock screw. It’s been tough finding a torx head alloy steel screw that fits.

I’m assuming you’re talking about a Glock MOS right? I’ve used those McMaster screws with no problems on a 407A with a G17MOS and with a 407COx2 on an M&P CORE (using 6-32x1/2” screws).

I do know that the McMaster stainless alloy screws have a head that barely fits the RMR and is too big for the Holosun. In my experience the regular alloy steel screws work fine. I’ll have to check this out.

[spelingmastir]

I’m assuming you’re talking about a Glock MOS right? I’ve used those McMaster screws with no problems on a 407A with a G17MOS and with a 407COx2 on an M&P CORE (using 6-32x1/2” screws).

I do know that the McMaster stainless alloy screws have a head that barely fits the RMR and is too big for the Holosun. In my experience the regular alloy steel screws work fine. I’ll have to check this out.

This is for an AIM Surplus slide with RMR cut. Thanks for all of the info you have provided.

[Archer1440]

I’m assuming you’re talking about a Glock MOS right? I’ve used those McMaster screws with no problems on a 407A with a G17MOS and with a 407COx2 on an M&P CORE (using 6-32x1/2” screws).

I do know that the McMaster stainless alloy screws have a head that barely fits the RMR and is too big for the Holosun. In my experience the regular alloy steel screws work fine. I’ll have to check this out.

As you know, (but for the edification of others)

Alloy steel screws are generally far superior in strength to stainless steel, which can have as little as half the strength (and tends to strip out a lot more easily as well).

[SoCalDep]

As you know, (but for the edification of others)

Alloy steel screws are generally far superior in strength to stainless steel, which can have as little as half the strength (and tends to strip out a lot more easily as well).

Very true… McMaster does have “alloy” stainless screws that have very high tensile strength and great corrosion resistance, but they are WAY more expensive and the head is larger. They will fit RMRs but not Holosuns.

For most users the alloy steel are best but for some using the RMR the alloy stainless may be worth it.

[Archer1440]

Very true… McMaster does have “alloy” stainless screws that have very high tensile strength and great corrosion resistance, but they are WAY more expensive and the head is larger. They will fit RMRs but not Holosuns.

For most users the alloy steel are best but for some using the RMR the alloy stainless may be worth it.

Correct, the specific one of the few alloys in stainless that is “strong enough” and available in suitable configurations is 17-4 PH (precipitation hardening) stainless, which is among the strongest of the stainless steels, and can be within 10% of the tensile strength of an otherwise equivalent carbon alloy fastener- IF it is properly heat treated.

The reason it’s more expensive is the material costs more, it needs slower cutting speeds in fabrication, and precise heat-treat is required.

That particular one is among the SS alloys that “stains less”- it will, in fact, oxidize in various conditions- but almost certainly not on one’s pistol.

[DpdG]

Any chance someone has the part number/link for the M3x6mm MOS plate mounting screws in the correct alloy stainless? CH used the same screws to mount a custom plate for my 320 and I'd like some spares but will not do business with C&H. Likely don't need a box of 50-100, but maybe 10 or so would be fine.

[Archer1440]

Any chance someone has the part number/link for the M3x6mm MOS plate mounting screws in the correct alloy stainless? CH used the same screws to mount a custom plate for my 320 and I'd like some spares but will not do business with C&H. Likely don't need a box of 50-100, but maybe 10 or so would be fine.

M3 x 6mm in coarse, or fine pitch? If 0.5mm (coarse) pitch you want these. The black oxide version: https://www.mcmaster.com/94414A712/

10 bucks for 100 of them. 12.9 spec for strength, which is the standard for this application. You won’t easily find these in stainless.

You can, however, get these zinc-plated which solves corrosion. https://www.mcmaster.com/90236A119/

$5.97 for a pack of 50.

[DpdG]

I think they are 0.5 thread. Would A286 stainless be inappropriate? I found these on McMaster, although they are showing about $6/screw: https://www.mcmaster.com/94331A102/