Red dot screw part numbers and ordering info

[Caballoflaco]

Yes, it was a McMaster torx drive. They thread into my slide very tightly and leave wear on the threads of the screw to the point I'm leary of attempting to fully thread them in. I have two M2.0 compacts and it's the same situation with both. They become very tight before even coming close to even seating into my Holosun/CHPWS plate. Any ideas about what's attributing to this? After breaking one I'm very nervous about doing it again. The Holosun and S&W hardware threads into the slide without issue.

My general rule of thumb when using new or replacement fastners is to first try them in the threads without any threadlocker. For small applications like this I want to be able to screw them into the threaded hole with a thumb and forefinger on the wrench making a movement not unlike playing a tiny violin. If everything fits good I’ll back it out apply thread locker etc and do the actual installment. (I spent 5 years wrenching on bicycles and stripping out threads on certain components could be a very expensive mistake)

I agree on seeing if you can get your screws and slide gauaged and possibly have the threads chased,

[maximus83]

The hex hardware included with my CHPWS plate also was difficult to thread. Could the threads in my slides be out of spec? Could it be a tolerance stacking issue due to the slide apparently being finished after they were tapped/threaded? This is the case for both slides.

I have the M&P 2.0 compact as well and just ordered the CHPWS. So shortly, I'll find out if I can repro your issue.

* I haven't noticed, do we have anybody here who has installed the CHPWS with its own or other 3rd party screws and no issues, on the new optic-ready M&P M2.0 compact?
* You mentioned the out-of-spec option, another option is maybe the M2.0 compact has a different spec for its screws than the CORE?

[maximus83]

It broke while I was installing my CHPWS plate along with the new McMaster hardware. The screw was about halfway threaded in, the screw head wasn't touching the Holosun yet. I noticed it was becoming tighter, at that point I should've stopped, but I continued tightening and it broke. I hadn't used my torque wrench at that point because the screw wasn't seated yet. That's totally my fault but I noticed that when threading the screws in my other slide there was flattening on the edge of the threads of the hardware. I was curious if that was normal or something you guys had experienced.

The first half of screw threads remain in the slide, with about 1/8" protruding from the top of the optic cut.

The hex hardware included with my CHPWS plate also was difficult to thread. Could the threads in my slides be out of spec? Could it be a tolerance stacking issue due to the slide apparently being finished after they were tapped/threaded? This is the case for both slides.

Got the CHPWS and mounted on the M&P M2 compact. Their hex screws were a little snug going in but not terrible. Backed them out to inspect; lower thread was polished shiny as you observed with a tiny shaving. Definitely there was tightness/friction on the threads, but not enough to be a showstopper. Seen threaded screws do this before when tight or right at the edge of the tolerances.

Added blue loctite and torqued down to 15 in/lb, went in fine. I'll get a pack of the McMaster screws as well to rate them.

[rca90gsx]

2.0 compact, factory plate, 3rd party screws. Everything fit perfect. Cleaned slide really well, cleaned screws, test fit by hand, threaded in perfectly. Installed with loctite very easily.

I have the M&P 2.0 compact as well and just ordered the CHPWS. So shortly, I'll find out if I can repro your issue.

* I haven't noticed, do we have anybody here who has installed the CHPWS with its own or other 3rd party screws and no issues, on the new optic-ready M&P M2.0 compact?
* You mentioned the out-of-spec option, another option is maybe the M2.0 compact has a different spec for its screws than the CORE?

[maximus83]

3rd party screws.

Which ones?

[rca90gsx]

McmasterCarr 6-32x1/2" alloy steel Torx head. That is the longest to fit. The 9/16" length bottoms out just before tightening all the way down, i didn't want to file those to length.

Which ones?

[maximus83]

Good to know, those were the ones I just ordered, hopefully they fit as well or better than CHPWS screws.

[SoCalDep]

Received another McMaster-Carr order on Friday. I ordered some of the 6-32 x 5/16" (Holosun - MOS) alloy steel screws and tested them on an MOS plate. The 5/16" screws flushed up perfectly to the bottom of the MOS plate - maximum thread engagement without any protrusion through the bottom. I'm happy with that.

I also ordered M3-0.5 x 10mm alloy steel screws (part # 94414A714) for my Sig P365XL and Holosun 507K. I wasn't sure since I was going by the Romeo Zero instructions which don't list screw length, but 10mm matched the length of the screws that came with the Holosun perfectly. I test fit and (re)mounted the 507K with the new screws.

I'm (based on Caballoflaco's excellent post above) revising my mounting procedure to include pre-fitting the screws without threadlocker to ensure they fit correctly. Therefore, my new steps are:

1. Make sure pistol is empty
2. Field strip
3. Prepare all surfaces (slide, plates, screws, threads) by de-greasing.
4. Test-fit screws in threads to ensure proper fit.
5. Apply threadlocker to screws (preferably Loctite 248)
6. Thread the screws until resistance is felt and then alternate slight increases in torque for each screw using a torque wrench to the lowest torque specification of any of the interacting components.
7. Place indicator marks on the screws/plate or screws/optic with a toothpick to make it easier to identify a loose screw.

After a near disaster yesterday and a couple weeks ago with a paint-pen, I will no longer apply the paint directly from the pen. I'll use a toothpick now just like I do with Torque-Seal. I apply the paint to one of the alcohol prep-pad wrappers that I've used and then use the toothpick. I'd be tempted to just get a couple small jars of Testers paint, but having to stir them may be more of a pain compared to shaking the paint pen.

[tlong17]

After a near disaster yesterday and a couple weeks ago with a paint-pen, I will no longer apply the paint directly from the pen. I'll use a toothpick now just like I do with Torque-Seal. I apply the paint to one of the alcohol prep-pad wrappers that I've used and then use the toothpick. I'd be tempted to just get a couple small jars of Testers paint, but having to stir them may be more of a pain compared to shaking the paint pen.

I’m glad you mentioned this lol. I had a disaster of my own attempting to use the paint pen to apply directly to screws. Not fun cleaning it out of the optic and slide. Not uncleanable but not fun! Toothpick works much better for me too.

[maximus83]

Now I'm having an issue as well. Hardware with the CHPWS stripped one screw trying to remove to replace with the new screws.

ETA got the stripped hex out using oversized torx trick. But the McMaster screws I'm having the same issue as @MD7305. They seem to be at the edge of the tolerance for the holes drilled in my compact; they don't feel right and are too tight to force. These screws aren't going to work in this gun.