I've been asked in PM by a couple of people about my M18 set up. Unfortunately the PM system is a bit buggy for me when I try to reply so I thought I'd make a thread outlining my primary M18 build and any changes. I have other P320s but I am focusing on my primary EDC/fighting pistol. Anyone else who wants to outline their build is welcome to post theirs up as well.

The M18
My primary started out as a standard M18. The reason I choose the M18 is that I was looking for a service style pistol that I could carry as my EDC but would also double as my go to fighting pistol. The theory being that, this way I would always have my go to pistol with me eliminating the need to carry multiple pistols in my gear in my vehicle. While I carry my rifle and depending on the day my pistol in a locked gun vault in my truck, the fewer guns in my vehicle the less chance of losing them if my vehicle is stolen. The M18 had a built in optic cut that multiple companies made adapter plates for that allowed me the use of the Trijicon RMR. After testing the P320 platform I had already done T&E on some parts that I knew I wanted to change. Initially I started this build using the 3.6" X-Compact pistol but I found the 3.9" barrel in the M18 just shot better for me.

The Adapter Plate
After researching multiple products on the market at the time I decided to go with the Bobro Engineering M17/M18 RMR adapter plate. I liked the built in rear sight of the Bobro option. It is simple and functional. The Bobro plate has built in bosses on the plate and the plate locks in using the guide cuts under the factory slide cover, indexing into the same groove as the factory slide cover. The Bobro plate I decided on also eliminated the top mounted LCI which I feel is redundant and unnecessary.

The Front Sight
Through testing with the Brobro Engineering plate with multiple front sights from .375" to .400", I landed on the .390" being the perfect height for my M18 with the Bobro Engineering plate with built in rear sight. I decided that I wanted a tritium front sight simply because I like having that little bit of insurance if my RMR goes down and I find myself in low light. The tritium option doesn't cost much and doesn't bother my sight picture. I ended up ordering the SG-160-390 tritium .390" front sight direct from Ameriglo. This is an inexpensive option that gives me a useable sight picture with or without the RMR in place. Plus it is only $50.

The Trigger and FCU
I decided pretty much right away that I did not like the safety. I elmenated the safety using the factory $12 safety pin direct from Sig. This was a very simple delete of the safety that took me about five minutes to perform using a video I found on YT. While I was deleting the safety I decided to replace the trigger with the Apex Tactical advanced flats face trigger and forward set trigger bar. The initial feel of the factory trigger was mostly okay but I like the feel of a flat faced trigger personally. Additionally I was not very happy with the reset of the factory trigger. The reset was soft and didn't feel very positive. The reviews for the Apex trigger seemed to be positive and addressed this issue. The Apex trigger and forward set trigger bar did help with the feel of the reset and improved its over all positive feel. My trigger is not a competition trigger, the weight is still pretty much the same factory weight, it is still a combat trigger just with a more positive feeling break and reset. For me this works great and I have no complaints. I also changed the standard slide release for a factory extended release like those found in the X series.

The Grip Module
After trying multiple grip modules with my X Carry and X Compact I landed on the Wilson Combat Carry grip module. I like the WC module because it has an excellent aggressive front and back strap texturing. Additionally the sides of the grip have a great pattern that offers a positive grip and allows moisture to channel away from your hand. My previous EDC gun was a WC 92 Brig Tac with WC/VZ grips. I found the WC grip module for the P320 follows this same shape in that there is a swell palm area of the grip but the grip slims down at the top giving the grip an over all slimmer feel. Additionally I like that the WC modules side texturing goes into the thumb area of the grip giving something for my thumb to "grab on" to. Finally I like the flaired and beveled magwell. It gives the effect of an aftermarket magwell without the added bulk and weight.

The Magazines and Mods
Coming from the WC Brig Tac and using 18 and 20 round Mec-Gar magazines I did not want to give up any capacity with the M18. The solution to this is the Taran Tactical +2 and +5 extensions. Initially I started out just using the +2 extension with my primary mag giving me 19 rounds in my primary mag and 22 round mags using the +5 extensions in my spare mags. I read a fellow members post on here one day and he reported good results with the Gram Engineering 11 coil and 13 coil spring and follower kits with the TTI extensions giving him an extra round on top of the +2 and +5 extensions. Testing the GE kits I found that this to be accurate. Using the 11 coil kits in my 17 round mags gave me a 20 rounds with the +2 and 23 rounds with the +5. Using the 13 coil GE kits with the 21 round factory mags gave me a total of 27 rounds per kit.

ACT mag
During this time I also began testing the ACT 17 round mag. These mags are made in Italy and other than a very slick, blued finish look identical to the standard Meg-Gar factory P320 mags. I have had no problems with these mags in both the standard configuration and while using them with the TTI/GE kits. These mags are now in my standard rotation. The upside is that they are significantly less expensive than the Sig branded Mec-Gar magazine that typically cost around $40 while the ACT mags can be found for $20. This is a big deal since the TTI extensions and GE spring kits add about $50 to the cost of each mag meaning that using factory mags cost me roughly $100 a mag vs the final cost using the ACT mags with the TTI/GE mod costing me around $70 a mag.

Weapon Light
After testing the Olight, Streamlight, and Surefire options I decided on the Surefire X-300U-B. While all three lights performed well the Surefire X300U-Bs mounting was the strongest, offered a solid length that helped act as a standoff in case of contact shooting and finally the Surefire option is made in the USA while the Olight is made in China and the Streamlight is made in China and assembled in the US. While I like the innovation coming out of some companies like Olight and Holosun at the end of the day I have to pick a side and for that reason the US made Surefire gets the nod.

MRDS
In my opinion right now there are only two MRDS brands that are worthy of consideration and that being the Trijicon RMR and the Holosun 508T. Both are great choices and while I like the innovation coming out of Holosun these days, like the weapon light, I have to pick a side and because of that I went with an American company and went with the RMR. I like the RMR. It does what I need it to do. I like the anodized coyote finish on the HRS version but IMO any type 2 RMR will work. It's a personal choice. For me I like the finish and the 3.25" MOA dot as well as the manual controls.

Barrel
This is an area I am still working on. The factory barrel is fine but to complete the LCI delete I need a non-LCI cut barrel. Since I am changing the barrel I figure I might as well get a performance advantage as well. Right now I have narrowed my option for a barrel down to the L2D Combat barrel or the PMM Gen 2 JTTC. Both have some advantages. I like the simplicity of the L2D barrel which is a drop in semi-match barrel with a target crown. Plus the L2D barrel is less expensive at around $215. The PMM comp and barrel gives a good performance bump but adds weight, a little complexity, and is roughly $125 more. That said the results others are seeing in terms of recoil reduction and making an over all flatter shooting pistol are hard to match. While I have been on the fence in regards to comps on fighting pistols, for the most part a lot of the bugs have been worked out and these days comps are pretty much figured out. I'm still undecided which direction I want to go.

For now this is what I am working with.
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Pretty sure most if not everyone who frequents this subforum is at least somewhat familiar with my builds, but I never miss a chance to whore out pics and details when prompted I won’t go into every detail on the various parts lists but I will talk about the commonalities that all three of them share, as those are parts that I’ve settled on as universally ideal for my preferences and purposes.

All three pistols are built or being built to use Icarus Precision Tactical Carry billet aluminum grip modules with Springer Precision ESP magwells; The IP grip modules have excellent grip texture and ergonomics and the added weight of the aluminum shifts the balance of the guns a bit more rearward so they don’t feel as front heavy. Of course the extra weight helps soak up recoil and muzzle flip, which in my book is always a plus. The ESP magwells obviously make reloads easier, but just as importantly enhance the ergonomics and assist in locking my dominant hand into the grip of the gun, creating pressure on both sides of my hand between the trigger guard and magwell. The magwells are large enough to be highly functional while remaining slim enough to avoid excessive printing when carried (AIWB).

All three pistols use Bar-Sto threaded barrels and Springer Precision compensators; The Bar-Sto barrels make the guns far more mechanically accurate than I’ll ever be capable of and the compensators do exactly what they’re designed to do - reduce muzzle flip and felt recoil when shooting high-pressure defensive ammo.

My trigger of choice is the Apex Tactical Flat Forward-Set trigger, the full kit with the over-travel stop piece; This reduces the overall travel of the trigger without reducing the pull weight below a safe threshold for a daily carried fighting pistol, while maintaining all the factory safety mechanisms.

Surefire X300U-B WMLs; Accept no substitutes.

If anyone’s interested in further details on parts and my experience with them you know where to look, or feel free to send me a direct message any time. If there’s one thing I’ve learned from a few years of working with this platform, it’s that no P320 build is ever truly “finished”, only waiting on the next innovative/effective enhancement to be discovered

You were a big help with the magazines and spring kits for me early on.

Great write up and pistol.  I'm almost done building the exact same thing.  Thanks for the heads up on the front sight.

I tripped and fell during a class and broke my 507C V2.  RMR all the way on everything I'm depending on.  The replacement (hopefully) Holosun will be dedicated for range plinking on my P80.

#twinning

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I did a few things differently from yours.

I used a 0.375" blacked out front sight from Dawson Precision.

I kept the LCI and used the compatible Bobro adapter plate.  I had read somewhere that deleting it can cause carbon accumulation on the RMR screen and I didn't want to replace the barrel too.

I use a WC compact grip, which I had to modify to fit the 15+2 magazine.

Lastly, I have an Apex curved trigger instead of a flat trigger.

Well might as well post mine as well:
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Sig M18, XCarry grip module, Holosun 507c V1.

Edited: Going to be getting some upgrades, will post them when completed.

My EDC P320 is no where near as cool as the others in this thread but I love my P320 and I do have bigger plans when they become more financially feasible. The build is relatively simple and straight forward:

- P320 Full Size
- Dawson Precision 0.455" Fiber Optic Front Sight with Green Rod
- Dawson Precision 0.450" Blacked-Out Rear Sight
- Apex Tactical Flat Action Enhancement Trigger
- Wilson Combat Carry Grip Module
- Streamlight TLR-HL 1000 Lumen

By no means am I finished building this out. I plan on picking up several of the ACT mags in the near future, and possibly a few +2 TTI base pads. Eventually I will also wind up either getting the slide milled for and mounting a Trijicon RMR or SRO or just buying one of the existing red dot ready slides. I still toy with the idea of getting an X5 slide for my future MRDS needs, but until one is available without window cuts that is just not happening. MRDS is on hold anyway until I get off of my full time college student budget.

That's a good looking shooter. P320s are quickly becoming like ARs for me. I spend a lot of time researching builds. I really would like to find a company that makes a chrome lined, cold hammer forged barrel with a reverse crown for the 3.9" size slide. It would be an over built barrel kind of like those found in HK pistols.

I like the ACT mags very well and have posted widely about them.
I could not however, get them to work with + extensions because my ACT mags have a "notch" at the base of the tube where a mag spring loop will get hung up.
This "notch" is a non-issue when used with standard basepads.
With a + extension, the hung up spring stopped any rounds from getting into into the extension.

Weird. All of mine work. Can you take pics of this notch? I'm curious about it. Thanks.

I went with the SIG Optics ready slide from the proshop and a ROMEO1Pro but same concept. I'm waiting on my suppressor height sights to arrive and debating between the Surefure X300 and the Streamlight TLR1 HL. I think I like the switches on the TLR better.

What holster is that?

Its a holster that I would not recommend in the slightest because the company that makes it has been pretty piss poor to myself and a few guys I know. But its a StandardCo USA Geronimo 2.0 thats been upgraded to Discreet Carry Concepts clips.

@granitestatemike

Where did you get the PVD slide release? I haven't seen those for sale.


As for holsters, I am using a Phlster Floodlight IWB. I have a Safariland ALS on order for my battle belt. The Phlster floodlight is nice. If you carry a fullsize light like the TLR-1 or SF X300 I recommend checking it out. The nice thing is it fits lots of guns so all you need is the type of light you like to carry. I've tested it with my M17, M18, Glock 19 and various Beretta 92s using the SF X300U-B. The only complaint I have really is when I got it all the screws were a little lose or just slightly tight. No locktite on any of the screws either. It wasn't the end of the world since I was switching out the soft loops it comes with already installed for the lock clips, (which they provide for free along with a different height mod wing as well), so I just removed all the screws, applied blue locktite and torqued it all down. Like I said not a big deal just something to be aware of.

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I can second the recommendation for the Phlster Floodlight, it’s an excellent solution for any gun with one of the two specified WMLs (X300U A or B model/TLR-1 and HL). Obviously mine is a bit cut up to accommodate the optic mount. My brother uses one as well for his M18 setup for 4 o’ clock IWB carry, I use mine in the AIWB position nearly right at about 12 o’ clock.



I’m also extremely pleased with the Tier 1 Concealed Axis Slim AIWB sidecar holster. Excellent fit and finish and very comfortable for daily CCW

Copy that, thanks!

They’re from an M17 commemorative gun that someone parted out. I think I paid $25 for the takedown and $15 for the slide stop.

Someone else bought the trigger, mag release, and back plate before me though

Ahh. Makes sense. Sig sells the take down and slide cover on their website. I bought the last slide plate cover the other day. I should be getting it soon. I thought about just sending all my parts out to be PVD' but it might be too coyote then.

Mine is an X-Compact
Apex trigger and bar
Wilson Combat module "bobbed" for comfort
Factory Sig night sights
Factory base plates trimmed and smoothed to fit better with the grip

Holster is from BraDeC
Mag carrier is from Red X Gear
Both have been upgraded with Discreet Carry Concepts Monoblocks

Speer Gold Dot 124gr+P

I carry appendix style. Mag and pistol on either side of my fly.

I like what you did to the backstrap area. I'm not that talented enough to do that though without destroying my module.

Oh cmon you can do it
Bench grinder, then a file, then sand paper

Anyone carrying a P320 compact with a red dot in a RCS Vanguard 3?

Here's mine. Love it. Fits my hand so well, and I wouldn't want it any larger for EDC. It's the perfect balance/size and weight without being full size and gouging my side or even the seat in the car. I'm just over 800 rounds of all types of ammo without a single malfunction. Makes me happy.

@JASIRR

Broke it how?  Glass cracked, stopped working, some other failure?  Did you drop the gun or land on it or something?  Sage's testing made it seem pretty durable.

I love Sage Dynamics. Single favorite YT channel and Aaron is the reason I got into pistol mounted red dot sights. That said, keep in mind his testing is a sample size of one, maybe two. Because of this I always take reviews with a grain of salt. Example, he tested the SRO and it was pretty much destroyed. I saw an SRO dropped at a class awhile back from chest height and it only had road rashes from the concrete. Lens was fine. I've seen broken RMRs and last month watched a 507C get launched off a slide and break. IMO Trijicons RMR is the best MRDS but Holosun is proven quality as well. I'd say they are not far from matching Trijicons RMR in durability. While I don't use them I'd trust my life to a 507C or 508T.

I do think it is important that when someone breaks something they should post about the how, why, and what. Pictures help too. It educates other users and helps designers identify potential failure points. Hopefully this leads to better MRDS in the end.

@superdrag67
@Charlie_Foxtrot


I was on the second to last stage, last day of our training class.  We were shooting barricades and I was moving from the barricade and about three steps into my run I tripped and fell on my front/right side, landed and popped right up and started running again.  That's when the instructors were telling me to stop.  I stopped and looked back and my pistol was laying on the ground where I fell.  It was in a Level 1 holster and had come out when I hit the ground.  How exactly it came out and what hit the ground I don't know.  The gun and optic didn't show any damage and I used it to finish the drill.

I didn't notice anything when I finished the drill with the 507.  A few days after I got home I was going through my gear and I picked up the pistol and did a quick look through the 507 and it was dim.  I was inside the house so I hit the button to make it brighter and nothing happened.  I thought the battery might be going bad so I swapped it out real quick.  No change.  I could turn it down one brightness setting, but it wouldn't increase from that point and was stuck on maybe the second brightness setting from being completely off.  I walked outside and it was bright as shit (solar) so I knew something was going on internally.

I assume something happened with the brightness switch or board inside the 507.  It would still work outside in the sun, but inside was a no go unless you could see a faint red dot.  There were no scuff marks or damage externally to the 507.  Yes I tripped and fell, but it wasn't something that made me think I needed to check my gear to make sure it still worked.  I understand things break and anything could break at any given time, but I'm not going to use the 507 in a EDC anymore.

Intresting. Does the 507C have a little cover over the emitter like the RMR? I've heard that these can sometimes come off the RMR and screw with the brightness setting. As I understand it, it's very common with the cerakoted RMRs. I'll see if I can find a photo.

@JASIRR

https://www.ar15.com/forums/Handguns/For-those-that-own-Trijicon-RMR-Type-2-s-Please-read-/23-182636/

Reading what you describe, the 507 was not hurt by coming out of your holster. More than likely it was a simple internal failure that would have happened if dropped or not. Send it in under warranty.

If you go over to Enos’s forum you will find a lot of different RDS’s that fail of all brands. Most carry optics guys have a spare optic(s). Running a RDS on a slide is pretty brutal on the electronics inside the red dot.

Unfortunately, this. That is why for carry/duty use back up irons are so important if you are using a MRDS. They all can and do fail. The only one that is probably indestructible are the FO only RMRs that don't have electronics. Though you can still break the glass. Plus they suck in bright sunlight.

Yeah, that one little trip changed my gear.  I didn't want to try to make a higher retention holster work for the P80. I needed a more mainstream pistol with good support.  Which led me to the P320's.  I now have a M17 setup with the RMR and a M18 kit setup with another RMR for carry.  Both guns have suppressor height irons. I just move the FCU around depending on what I'm doing.  So I have that backup in case something goes wrong.  2 is 1 and all that.

What kind of holster was it? Not a Safariland I hope.

Just realized it was a P80 frame. Missed that on the first read.

It was a C&G holster, definitely not Safariland.  I have a Safariland 6390 for my 320's now though.

Ordered one for my M18 last weekish. Hopefully it won't take the full 30 day lead time.

I still have one on order from Safariland that I ordered on 9/25.  I ordered it before I found one on copquest.  I watched copquest everyday for a couple of weeks and they finally had one show up in stock in ranger green .  I ended up painting it FDE once I got it in.

Thanks for the reply.  I have a Holosun 407 and 507C on range/fun guns that haven't given me problems yet, fingers crossed they won't.  Interesting to hear issues others have had with them though.  I keep RMR's on anything I carry just because that's all I feel comfortable with but I honestly prefer other a couple of other dots over the RMR.  Still want to get my hands on an SRO.

Wifes X-Compact with the new Bushnell RXS-250. Finish matches the Sig perfectly, like it's made for it. Beefy, solid, nice fat fasteners, and feels like quality. I'll get it to the range once it warms up a tad and stops raining here. I think I'll be switching  to carry this instead of the X-Carry. ;)

Very sharp looking

Sig is now selling the PVD back plate for $10 I have one in shipping now. Just waiting for arrival.

As for my EDC p320. I change it up so much it’s almost funny.

Currently it’s an M17 FCU, 357Sig top end on a Wilson carry grip.

The second one is a x5 FCU with an M17B top with a griffin threaded barrel and comp, and a Docter red dot. The grip is a B&T module with the stock removed. It’s a dedicated red dot gun with not even a front iron sight.

My  P320 EDCs (well and one P365xl) I am a fan of the platform!

Details on the PMM RMR Rear sight? How does it attach? They have not posted very many details about them.

I have a Wilson grip frame on my P320... I *NEED* WIlson to drop a P365 grip.

Just had the slide refinished in Federal Standard FDE Cerakote Elite. Not that happy with it. Textually it’s slick and it is shiny. I have a second slide getting finished in the CE M17 color which is supposed to be a match. If so I’ll get this slide refinished.

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That surefire really is a dead on match to the grip module in photos. Damn.

I went all out. I have large hands so I got a large module. Wasn’t grippy enough so I added Talons. Still wasn’t big enough so it got Hogues.

Did it get switched to the “auto” setting? Because it sounds like it did.

Heads up! That M17 Elite cerakote is not quite a match for the slide: (pictured on left)
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The color you will want is Troy Coyote Tan:
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What would you like to know about it? it sits inside the RMR, over the emitter window (actually helps hold it in). Its a very slick setup!

How do you like the PMM comps? Are the barrel/comp kits or aftermarket barrels?

They look sharp.

Love them! eats anything and makes a giant difference, especially on these shorter barrels. I also have one of their dual port setups as well.

They are sold as barrel/comp packages and complete builds

Just added some factory PVD coated coyote parts. I’m going to send an Apex trigger, slide release and mag release out to be pvd in coyote to match. I have a barrel from L2D in black DLC on the way. Then I am going to have the slide refinished in the Troy FDE cerakote. That should complete this build. Then I am going to start my commander build. A carry II frame with a 3.6” barrel. Essentially the same as my M18 but with a 3.6” barrel, Surefire XC FDE weapon light and an RMR HRS.

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I still need to install the sear housing and I updated the extractor with a tool steel Lone Wolf extractor. Not sure it’s an upgrade I just like the profile better.