I'm considering picking up a used P226 to have milled for an optic. Obviously, it will have to be one of the newer milled slide guns, as the folded slides don't have enough material to mill out for an optic. What I'm finding, though, is that most companies indicate that their optic cuts on the P22X slides will expose the firing pin block channel, and the spring will now have to rest against the optic mounting plate, or the bottom of the optic itself. This seems less than ideal.

So my questions:

1. Are the factory P22X RXP slides that are cut for the Romeos this same way? If you take the dot off, is the firing pin block channel left open?

2. Is there anybody out there cutting these in a way that avoids this, or any specific optic/cut combination that might allow for a cut that doesn't do this?

3. For those of you who have a 22x gun milled for a dot, have you had any issues as a result of this arrangement (beyond obviously being permanently married to a specific type of optic on that slide)?

I've milled several.
I can't answer 1 or 2. For #3, no issues across 3 slides. Mine are rmr pattern milled and the RMR sealing plate is used.
I think (its been awhile) that one of the people who milled a p226 slide for me may have sent me a different spring in case I had issues, but don't quote me on that. In any case I have had no issues. At this point I think pretty much everybody who mills should have a pretty good understanding on the issues. Sadly I've used 3 different vendors with success but 2 of them no longer do sig milling.

Awesome, thanks for the feedback I appreciate it! Can you remember the name of the vendor that's still doing P22X slides? I used Maple Leaf for my 320 and was happy with them, but I think they only do the striker-fired Sigs.

Following

I only have experience with long extractor slides.

I had a P229 slide milled for RMR by Parker Mountain Machine. They did a really good job. About a coil was clipped from the exposed safety lock spring. I only ran an an RMR with a sealing plate and it was fine. You do have to be a bit careful not to trap a 'leg' of the spring between the plate and slide when the optic is installed. An SRO probably would have worked as well (no sealing plate required) but I never tried it because the front of the optic would have been a little too far in front of the breech face. The extractor pin was also shortened. I sold that slide.

I replaced it with a P229 Pro Cut slide. Sig must use a different safety lock spring and obviously use a shortened extractor pin because nothing is exposed with the cover plate removed. I didn't like the Pro Cut slide and replaced it with a factory RXP slide and the safety lock spring isn't exposed on that one either.

Finally, I recently got a P226 Legion slide and it doesn't have any exposed spring either.

My conclusion is no P-Series factory milled slide will have an exposed safety lock spring. I don't know whether anyone who mills P-Series slides can avoid exposing the spring, but it may depend on the slide. I took apart the P226 Legion slide and Sig uses a different safety lock and spring and a shortened extractor pin so that no parts are exposed. I have a replacement long extractor pin and it's obviously the same pin but just shortened at the factory.

I was looking in to milling another long extractor slide, this time for a P226. I asked Vulcan Machine Werks if they could mill a long extractor slide for a Romeo-X Pro and they said yes but I suspect in that case the safety lock spring would also be exposed but I didn't ask them about that specifically.

quote:

Can you remember the name of the vendor that's still doing P22X slides?

PMM did my first one many many years ago and the service still seems to be available on their site.

Thank you both, that's very helpful and useful information. It sounds like I may need to source a factory cut slide if I really don't want the firing pin block channel exposed.

I know that Sig is offering some of the new P320s with screw holes for both the DPP and RMR footprints....does anybody know if that's the case on the P226/P229 RXP models?

I can't answer your specific question, but I can provide a caution if you are trying to mount an RMR. The RMR design provides two screws and two recoil lugs (for lack of the official term). Many generic designs don't have the lugs and its ultimately fatal. The screws eventually break form the sheer forces. This has been the experience of a friend of mine who I compete with every week, her 320 breaks screws all the time. Now I have had maybe 50 guns milled and there are some other ways to deal with this like having the front 'ledge' of the cutout can take the forces but that requires that the cutout get milled to the exact length of the specific optic (because there is a pretty big variance on RMR's). But personally if you have it done by someone competent I don't get what you are concerned about on the FP channel. I've tens of thousands of rounds across multiple examples and its never been an issue.

Yeah, I've heard of the screw-shearing problem with the RMR. When Maple leaf did my P320 slide they left partial recoil bosses (it's not the full circle...maybe 2/3 of the pie IIRC...it's been a while since I've had the optic off to look at it), and I've had no problems.


I've seen that some companies offer plates to supposedly fix this problem, but I'm not entirely clear on how that works. The photos I've seen show a plate with recoil bosses that goes between the slide and the optic. I don't understand how that solves the problem, though, as you've now just transferred the same force to the screws from the plate rather than the optic itself. The only thing I can think is that the plate fills the cut more precisely than the optic would and thus transfers the force to the edge of the cuts rather than relying on the screws.

I don't know if Sig is adding the RMR hole pattern to RXP slides. The one I have doesn't have them. C&H Precision will add them for a reasonable fee and probably any machine shop could do it easily. I used a C&H "filler" plate to mount an SRO on the RXP slide and that's what it's made for, to "fill" the gap. The fit is not incredibly precise, at least it wasn't on mine. I didn't shoot it long enough to experience any problems, I removed the SRO and put a Romeo1 Pro on it (I have too many optics and can't stop switching things around).

The R1P isn't the best optic in the world but it's fine for my use (a couple of matches a month). One thing I do like about the Sig optics is that the screws are substantial, especially compared to the tiny screws that come with the Holosun 507Comp, for example.

quote:

Originally posted by 92fstech:
I've seen that some companies offer plates to supposedly fix this problem, but I'm not entirely clear on how that works.

They are "filler" plates. Using a Sig factory RXP slide as an example, the optic cut is sized for a Sig Romeo 1 Pro or Leupold Deltapoint Pro. The slide has additional drilled and tapped holes for an RMR pattern optic but RMR pattern optics are smaller front-to-back than a R1P or DPP. It's a bad idea to simply mount one of those smaller optics to the slide as with the optic cut being bigger, and the slide lacking recoil bosses to absorb the load, all the recoil forces get applied to the screws as a sheer force which they are not designed to handle. The filler plate has extra material that fills in the extra space of the bigger cut when using the smaller optic. When mounting the optic, you put forward pressure on the optic which is up against the filler which is then up against the slide optic cut, so no gap.

That makes sense, thanks. The only two milled guns I have are a Sig P320RXP with the factory-installed Romeo, and another P320 that was custom-milled by Maple Leaf for the RMR, so I haven't had to deal with any of this plates and fitment stuff yet.

quote:

Originally posted by cyberiad:
I don't know if Sig is adding the RMR hole pattern to RXP slides.

From what recall and what I experienced when Sig first came out with the Romeo 1 Pro slides, the additional RMR holes were added after the initial release. I believe the Sig official designation of "RXP" came later yet and all RXP slides should have both sets of mounting holes.

quote:

Originally posted by cyberiad:
C&H Precision will add them for a reasonable fee and probably any machine shop could do it easily.

Maybe I was an outlier but I had an early P229 Romeo 1 Pro slide that I sent to C&H for that exact work and they botched it. When I received the slide back there was exposed stainless on the rear rails exactly where you start to mount the slide back on the frame. It was a brand new slide when I send it in and while not happy about it, the damage seemed fairly minor. That is until I tried putting the slide back on the frame and it wouldn't go on. Made sense at that point with where the exposed stainless was at they pinched the very end of the rear rails. They asked to have the entire pistol sent to them for evaluation by a gunsmith and I believe they covered the shipping. The last straw was when I called to check on the evaluation and the person I spoke with said the slide went on the frame just fine. I got the impression it didn't even make it to the gunsmith.

Well that's not a good experience. Did they ultimately fix it and did it work when you got it back?

I assumed the frame rails would be gouged or marked in some way so told them to just send it back to me. Thankfully they were not. I fixed it myself, just took a small amount of stoning on the inside rear tips of the slide rails.