Took them more than a month, but worth the wait:





I guess I'll just ignore this extra set of drilled/tapped holes in the RMR position.  They can't be there.  





Did they really not infer that the slide I received was drilled/tapped for an RMR from the question?  The exact product for which I submitted the question on its product page...and which I ordered from Proven Outfitters several months ago.  Excellent CS there Sig.  Take the rest of the week off.


CHPWS finally hooked me up with a set that fit, cut to length...and they claimed they were 6-40, so it really is still a bit of a mystery.

I bought an M17.  Evidently mine was NOS, because it was only drilled and tapped for the Romeo1 Pro/DPP.  I called and asked SIG and was told that the M17s and P320s started being tapped for both later in production, so that was why mine only had one hole set.  A DPP will fit as is, but an RMR will need an adapter plate, IIRC.

Yes, an R1P and DPP will be direct mounts.  

Even with RMR holes, you'd need at least a sealer plate for an RMR on an M17 and more likely a filler plate given the larger R1P/DPP cut and lack of recoil bosses/lugs on the slide.  But I'd still probably get a somewhat thicker RMR adapter plate given that the M17's rear sight is integrated into the optic plate and lost when that plate is removed.  The Bobro adapter plate is a solid solution.  Springfield has one as well...but, you know, Springfield.

Did you get the CHPWS plate or just ordered the screws from them? I order their plate which came with the screws. I also installed the sealer plate just in case.

I ordered their adapter plate and then, after realizing there were RMR holes under the R1P, swapped it with their thinner filler plate.  


Adapter plate:




Filler plate:




The filler plate came with Torx head screws that would not fit in the RMR holes on the slide, even though I selected the correct option on the CHPWS order page...and even though CHPWS verified they sent the correct size (6-40).  




And I was not alone.  I know of at least two other guys who ordered the same plate and couldn't get the screws to fit.  

So I contacted Sig CS, via email/web form and telephone, to get their official word on the the proper screw size.

Sig telephone support swore they were 6-40 and that the screws I had must be the wrong size, but they were out of stock and couldn't sell me any.  Days later, Sig email support also told me 6-40, so I followed up and reminded them what was in my original support request - I tried 6-40 and they don't fit.  They then responded by telling me that my slide wasn't drilled for an RMR.  I sent a picture back showing it was and then they responded by saying "oh, yeah, the screws you need are 6-40."

So I ordered 6-40 screws from a different source, but they didn't fit either, which is when I engaged with Sig again, asking them to take the slide back for inspection.  They refused, so I asked CHPWS if they would do it, and they agreed.  A couple days after they received it, they had it back in the mail, with hex key flat head screws that did fit, cut to length.

I had also submitted this question on the product page and received the answer posted above, 5 weeks later, after the problem was solved.


What a complete goat rope.  But I am happy now and she shoots great.  I can't wait for the Obsidian 9 to get out of jail.





BTW, you shouldn't need the sealer plate with either their adapter or filler plate.  The plate will mate with the gasket on the underside of the RMR and seal it.

Do you know what size the screws are that CHPWS sent you? I’ve got a bag of mounting screws in all different kinds of sizes, but I don’t have one that fits the rmr holes either.

Not sure, and I've got more than a bag.




I followed up with CHPWS after the fact but didn't get a clear answer...and since they sent me a set that worked, I let it go.


Sig sells a sealer plate that comes with a set of screws, so that's one approach.  They were also supposed to send me a set when they got them in stock, but that was a couple of months ago, and nada.  

Another guy I know did get Sig to agree to take his slide back to check those holes.  They eventually got back to him, saying the RMR holes were drilled/tapped in spec and they were sending the slide back with a pair of screws that fit.  And the screws they included were for the R1P/DPP mounting holes.  

I wonder if it was just a fluke or if CHPWS has some rookies wondering around answering phone calls?
I am 2 for 2 without issue. I had to shorten the right side screws on both, but both mounted without an issue. I used the screws CHPWS supplied both times.


Cp

Ordered some 6-40 screws for one of mine two weeks ago on Amazon…. Been lost in the mail for awhile now..  if they ever show up I am hoping they work at this point lol

I didn't see this post and asked the same question because I have the same problem with a weird threaded slide. I bought a chpws plate that makes the Holosun fit tight. It came with different length screws but none fit more than a couple of threads before it gets tight. Do I need to just chase the threads with a 6-40 tap? Seems that would make life easier.

Having chased the threads on a 320, you might want to read this thread:

https://www.ar15.com/forums/Handguns/Screws-for-drilled-tapped-RMR-holes-on-XSeries-slide-/14-199853/

We did get it resolved, but it was more work than I had anticipated. But, based on my experience, yes, some 320's have 6-40 tapped holes that need to be cleaned up. Best of luck!

This is apparently what you need, sold individually:

What a cluster.. Sig really needs to sort their slide cuts out. Make one cut and sell adapter plates for the corresponding optic footprint. Their RMR holes are just wasted machine time since direct mounting an RMR using their holes is a disaster waiting to happen. The lack of bosses means that if you direct mount an RMR using their provided holes, at some point the screws are going to shear off and your optic is going for a ride.

The simple answer is that they should sell a filler plate, like CHPWS does, with the correct mounting screws for however they tap the RMR mounting holes.  Instead, they sell an RMR sealing plate, that neither fills the cut nor provides RMR bosses/lugs.

I don't get it.  At all.

Where are these Sig Sauer screws sold? I can't find those anywhere.

Directly from Sig, and you'll need to call them because they don't show up on their site.

Thanks for the info! I ordered a CHPS plate first and we'll see if that works. I have a new pistol with the RMR cuts but there screws I have don't work ( they may not be correct and came with the SRO and Springer plate I used on my X-Compact so I'm not upset yet.