Got RMRcc.  Got the appropriate mounting plate for p365xl.

The screws in the gun that hold the plate and rear sight on are too long.  They bottom out against the bottom of the RMR and can't get it tight.  No other screws came with the pistol, and Trijicon just says "use Sig supplied screws" so I assume they mean the ones that I took out to remove the stock plate.

Am I doing something wrong?  Do I need to buy shorter screws, and what size?  

If I put the plate on without the RMRcc, the screws from the slide stick up about 2 threads above the mounting plate.

You have to shorten them.

hard to do without buggering up the threads.  don't have a tap or even a nut to chase them.  ETA: I guess I can use the plate to chase them if I grind them after threading through plate off the slide....

Anyone know what size they are?

someone must have mounted an RMRcc on a 365xl.....

Yes, I have. I’m telling you that you have to shorten the factory screws to install it. Yes it’s odd, yes it’s a PITA, but that’s what you have to do to put the RMRcc plate on the gun.

Thanks.

I screwed them into the plate and used a Dremel sanding drum, then backed it out the plate to chase the threads (although no resistance so I think the threads were pretty clean).  For anyone else who wonders best way to do it.  I was afraid if the threads really got buggered it may ruin my plate but no issues whatsoever.

having a hard time getting sight picture, but took it to the range yesterday and loving it!  Need to practice more.

I hit them with the grinder and just ran them back into the factory plate to make sure the threads were good and to not mess up the threads on the adaptor plate.

Which optic do you like more?  The RMRcc or the 507k?  I'm trying to decide between those two for my P365XL.

I like the RMRcc more, but I like the 507K more on the XL. The issue for me is the mounting plate. It’s too high, the factory screws that hold it on are puny, and it deletes the BUIS.

With the 507K it bolts right on very low with no plate, and has a built in BUIS. The adjustment buttons and dot also sucks compared to the RMRcc. I also had to buy four of them to get two good ones. The first I bought came in fine, the second I bought had a chipped lens, and then it’s first replacement had a cracked lens. It took another replacement to get one that was ok out of the box.

I’ll continue to run the 507K on both of mine until either a better mounting plate comes along. Or Sig makes a non cut XL slide that I could send out to be milled.

Thats the reason I went with the holosun over the rmrcc. I feel direct bolt on is better for me and I hate how high the rmrcc looks.

I have also mounted an RMRcc on my P365XL slide via the adapter plate and I too shortened the screws, after contacting both Trijicon and Sig about the issue. Neither one of them supplies the correct length screw for this combination. While I am a bit of a Trijicon "fanboy" they completely screwed up not using a universal mount footprint for this optic. Sig has no plans of ever changing their mount pattern (or offering an XL slide without the optic cut), and I have contacted every machine shop that does slide cutting that I could find to see if they could convert the OEM cut to the RMRcc cut - no one is willing to try it even when I offer to bear full risk of my slide acting as a sacrificial lamb for an entrepreneuring machinist.

The RMRcc sits entirely too high on the XL to be usable, it's very awkward. I feel like I'd get shot before I'd find the dot on this gun in a real world scenario, so it's out for carry. If you look closely at the RMRcc it has a lot of aluminum below the glass, so it could stand to be sunken into a slide as low as possible. Will either purchase the Reptile slide from Norsso but would rather have one in the XL length.

Too bad because the RMRcc seems like a very robust optic (contrary to social media complaint clubs I like the battery compartment design), but Trijicon missed the mark big time with the footprint. May even cut the product lifespan pretty short if they don't get a gun manufacturer to jump on board with their footprint ASAP.

I am fixing to pick up a XL, and I want a red dot.  I am shy of Holosun, just due to a bad experience with one of their aimpoint clones.   I also do not like the plate for the RMRcc, but i know that trijicon will be the better optic by far.   Any other good options out there?  Seems like they are all made in china like holosun, but minus the following.   How usable is the rear buis on the holosun?  you know, in case it craps out.

Unfortunately the 507K is the best thing that fits the cut. It is what it is. Wish it was and RMRcc but it’s not.

If you haven’t purchased yet, just buy a regular P365 and swap on a XL grip, pick up some XL mags, and have ATEI mill it for an RMRcc for you. You won’t miss the half inch of barrel and slide. Win win.

That is the way I am leaning.  I found a P365 tac pac with the 12 rd mags and no 10 rounders.  I assume I can remove that grip adapter and they would fit flush with a xl grip module.  With the tac pac, a couple 15 rd mags, xl grip module, flat trigger and night sights, its going to be around $850 shipped and transfered.  I am leaning heavily this way...

Any trigger springs or other mods I need to pick up?

I was also looking at Fabricated Arms for the milling.  Are they good to go?

You’ll need the flush base plates to convert the mags since the tac pack won’t come with them but they’re like $5 a piece.

I personally wouldn’t change trigger springs and stuff on a carry gun, and I’d never send a gun to anyone but ATEI for milling since they’re the best in the business, and have good lead times with finishing.

Have you shot both of them? I personally miss the half inch and shoot the XL much better. I have no interest in the regular 365. Don't take others subjective advice as definitive.

One bad experience, with one optic and you won't purchase another one of their products? If I did that, I wouldn't be able to purchase EOTech or Aimpoint either.

Check Sage Dynamic's video review of the 507K
and the one on the RMRcc
I'm running a 507C, 407C and 407K with zero
issues of any kind, they have the features I want,
while I haven't dropped them on concrete, they've
all been carried for month's of 12+ hour days,
getting under car's, running a chainsaw etc.,
nothing's moved, zero's maintained shake awake
still works fine etc.  
I get the whole made in china thing but...
seems to be a well mad product with desirable
features with from what I understand, a warranty
they stand behind, for considerably less money.

I’ve got two 507K’s on P365XL’s. The first one arrived fine, but the second was defective out of the box and then the third too. It took getting four of them to get two working ones.

Then a couple months ago knocked one of them off my nightstand on accident, fumbled with it on the way to the floor so and it landed on carpet and the zero shifted. A little over 2’ drop onto very plush carpet caused a shift, that doesn’t exactly give a lot of confidence.

There are worse red dots though, it’s the best of the ones that mount to the RMSC footprint but it’s still a Chinese piece of shit.

I'd wager that about 80% of the issues you hear about defective Holosuns are from people who are too lazy to read the instructions and install the battery upside down. I had two friends who both claimed they had defective units (reticle kept blinking) from the factory. I asked both to double check their battery and sure enough, upside down.

Units with solar panels will have just enough power to flicker with the battery installed wrong. Ask me how I know...

507K’s come with the battery already installed, but even if they were installed wrong at the factory I’m pretty sure that wouldn’t cause the lens to be cracked when you open the box up.

Holosun replaced my new out of box one, chip in the lens.

I'm just curious, did you order it from Amazon?

Someone with Prime can beat the shit out of something, say that they decided they didn't want it,  return it for free and after a feeble examination by an Amazon half wit they will put it right back on the shelf and sell it.

I've received a few used items, so I buy very little from Amazon anymore. I can almost always find a better deal from another retailer, using email sign-ups and coupon codes, anyway.