SIG P320 RX review: Ready-to-rock optic equipped pistol

alma-cole-sig-p320rx-01Optic equipped pistols are not a new idea, but until recently they were a curiosity reserved for high-end “race guns” which are far from common. While manufacturers have made strides in bringing the optic equipped pistol out of obscurity, SIG SAUER® may have just released what has the potential of being the first truly mainstream optic equipped pistol, the SIG P320 RX.

SIG SAUER P320 RX

Other pistols that are optics ready – where the slide has been milled to allow users to purchase and install a separate micro red dot sight from another manufacturer – have been on the market for a few years. What sets the SIG P320 RX apart is that the pistol is optics equipped.

The RX ships from the factory with a SIG SAUER Electro-Optics brand Romeo1™ reflex sight installed into a specially cut low-mount dovetail in a P320 slide. There is no need to buy a pistol and spend an additional $200 to $700 on an optic that must be installed. Those configurations will not be serviced under the same warranty as the pistol. Having the gun – including the optic – provided by and under warranty by the same manufacturer may open up doors for optics-enabled pistols to find their way into more duty holsters, and will certainly remove complexity and intimidation from the average shooter who may be interested in red-dot equipped pistols.

Since SIG is selling the P320 pistol and its own red dot as a package, it is also able to offer it for a lower price than it would cost to buy an optics ready pistol plus red dot. The introductory MSRP for the P320 RX (complete with optic) is $799. Cabela’s stores were fortunate enough to score an exclusive deal with SIG for the initial launch of the P320 RX but you can now find the gun at many SIG dealers.

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Romeo1’s 3 MOA dot with co-witnessed night sights.


The deal gets even better when you learn all P320 RX guns are equipped with suppressor height co-witnessed SigLite night sights. These sights give you a backup capability and provide some comfort since you will always have a good set of sights available should they ever be needed. Also in the box with the RX you’ll find two pistol magazines, a nice cover for the Romeo1, a sight adjustment tool, and a sample of Lucas Outdoor Line Extreme Duty Gun Oil.

P320 RX in Competition

Seeing the trend in optics-equipped and optics-ready stock guns, the United States Practical Shooting Association (USPSA) recently launched a provisional Carry Optics division. This division closely mirrors the existing USPSA Production division but with the addition of a slide mounted optic. This division is appealing for anyone who would like to take advantage of practical optic-enabled pistols without having to go all in for USPSA Open Division.

Even out of the box, the P320 RX is absolutely ideal for Carry Optics and should prove to be extremely competitive and popular. At the first USPSA Carry Optics Nationals held earlier this summer, multiple shooters jumped into Carry Optics with both feet by competing with the P320 RX. Shooting his P320, Team SIG Captain Max Michel won the inaugural Carry Optics National Championship. The P320 RXs shot during Nationals and since then have been holding up extremely well. We are just scratching the surface of understanding what this gun and optic combination is capable of doing.

SIG Electro-Optics Romeo1 Micro Red Dot

While the P320 certainly is a very notable and capable firearm, the star of the show for the RX package is, of course, the optic. The Romeo1 is not a rebrand of any reflex sight on the market today. It is a labor of love in development and refinement over the last few years by the SIG SAUER Electro-Optics Division. Unlike many other red dots the Romeo1 was designed from the ground up specifically for handgun mounting. Because of SIG’s ambitious plans to release this optic from the factory on both standard duty pistols, and heavy-hitters including the P220 in 10mm, a considerable amount of time and attention went into ensuring that the sight would be able to withstand the punishment.

The first thing you may notice about the Romeo1 is its attractive styling; however, those lines serve a very functional purpose. The front and back of the Romeo1 are canted in like a giant rear sight might be. On further inspection you may notice the low mount slot in the RX slide used for mounting the Romeo1 is cut as a large dovetail. Yes, installation of the Romeo1 requires you to drift the optic in from the side in a dovetail like you would do for traditional pistol sights. This gives the Romeo1 a good seat on the slide before the two set screws are put into place.

The housing itself is CNC milled from aircraft grade magnesium, giving the Romeo1 very good strength while keeping the weight down. To improve its ruggedness further the housing is two-piece ensuring that the lens is firmly captured. Additionally all of the internal electronic components have been bedded in epoxy to prevent them from working lose in recoil.

With a CR1632 battery installed, the Romeo1 weighs only 0.8 oz. Even with an optic that is so light, SIG has worked additional magic with slide lightening to keep the overall weight down. With the Romeo1 and the taller backup sights installed,  the RX slide is only 0.2 oz heavier than a standard P320 slide.

The rear of the Romeo1 has a small notch aligned with the notch in the rear backup night sights giving plenty of clearance to see the co-witnessed front sight through the optic. Also, the Romeo1 is waterproof rated at IPX-7.

Close up shot of the Romeo1’s top load battery compartment. Tighten well before shooting.

Close up shot of the Romeo1’s top load battery compartment. Tighten well before shooting.

The Romeo1 features a 3 MOA red dot with five illumination settings controlled by two buttons on the left-hand side of the optic. The five settings provide a good range of brightness with the dot remaining clearly visible outside on the brightest days. The 3 MOA is sharp and makes accuracy work relatively easy when you do your part on trigger control.

Holding in both buttons for three seconds will turn off the dot; however, most users will never need to do that since the Romeo1 includes SIG’s Motion Activated Illumination (MOTAC) system which puts the dot to sleep after about three minutes without motion. I tested this while driving in a vehicle and found that road motion while riding in a holster wasn’t enough to wake the dot from sleep but as soon as I drew the gun the dot would be instantaneously there.

If you didn’t know that the battery saving feature was included you might never even notice it. The top load CR1632 battery offers convenience of being able to change the battery without having to remove the dot; however, a few early adopters have seen issues with the dot shutting off in recoil. This has been due to not having the battery covered tightened down sufficiently. The fix is easy: use a good screw driver (instead of the included sight tool), and tighten it down hard. I did this when I first installed the battery in my Romeo1 and have had no issues with the dot cutting out. I also marked the battery cover with a Sharpie so that I could see if it started to come loose; it has not.

The glass aspheric lens has excellent light transmission with no visible distortion, and making sighting adjustments to the Romeo1 is easy since SIG’s Truhold locking system doesn’t require messing with locking screws to hold adjustments. Just set the windage and elevation using the market 1 MOA indicators and start shooting.

Should any issues with the dot be encountered, SIG covers the Romeo1 with its fully transferrable lifetime Infinite Guarantee on the hardware, and a 5 Year Warranty on the electronic components.

Range Time and Competition with the P320 RX

Three shot group from 22 yards shot during my initial range session with the P320 RX.

Three shot group from 22 yards shot during my initial range session with the P320 RX.

The P320 has been noted as a very accurate duty pistol out of the box but the addition of the Romeo1 really brings out the P320’s accuracy potential. As a competitive shooter, I am fortunate to be able to compete frequently and a shoot whenever I can; however, I have never been that good at shooting groups, especially at distances beyond 15 yards. This is in part due to astigmatisms, imperfect correction with contact lenses, poor indoor lighting, aging eyes and whatever other excuses I can think up.

As soon as the coveted package containing the RX slide arrived from Bruce Gray at Grayguns, I headed to my local indoor range to see what it could do. I was floored when within the first few rounds down range I found that with the P320 RX and SIG Elite Performance Ammunition I could shoot a group smaller than 1” at 22 yards while resting my hands on the open bench. That type of laser accuracy is just simply something that I haven’t been able to do with any pistol, ever. Even 25-yard plate racks become easy when all you have to focus on is trigger control.

Since I was already very familiar with the P320, adapting to the RX took no real effort. You simply hold the gun ever so slightly lower than where you hold for traditional sights, find the dot, and put it on the target. Before shooting I was concerned that I might find the co-witness sights distracting; however, I have not found that to be the case. When I am using the dot I don’t notice the sights at all; however, I have found them to come in handy as an aid for finding the dot when I am shooting with one hand only or in other awkward positions. For new shooters I have found it useful to explicitly remind them there is no need to line the dot up with the traditional sights.

The second time out I shot with a larger group who ranged from casual to first-time shooters. Out of the six pistols I brought with me, one was the unanimous favorite, the RX. The simplicity of being able to focus on the target and not have to worry about sight alignment made everyone shoot more accurately and helped to better show the new shooters what they were doing and what needed to be corrected. For this same reason I plan on putting down my iron sighted P320s to in favor of the P320 RX for the next few months. The red dot makes it much easier to see how your trigger control might be disturbing the sights, and allows you to better see and focus on recoil control; both areas where I need to improve.

On September 11, I was fortunate enough to spend the day at shooting a small local USPSA match with P320 RX on the Marine Corps Base in Quantico, Virginia. This was my first Carry Optics match shooting the RX. The stage where I started had a “Texas Star” some at distance and had the longest shots of the match. I took two extra shots on the star simply because I wasn’t waiting for my dot to cover the plates. Once I did that they went down with no difficulty. The remainder of the stage felt slow, but I ended up with a stage win by 11 percent.

I did have some difficulty finding the dot on a classifier stage that required weak hand shooting so I had to index of the backup sights to get the dot on target. I also need practice on shooting closer targets at speed since I was being more accurate than needed on at least one close array. Out of 44 shooters in attendance at the match I finished in second place overall with 99.36% percent of the Open division winner’s score. Best of all I easily shot the most accurate USPSA match of my 14 year shooting career, scoring 96% of all points possible. I definitely have to work on improving speed but I was extremely impressed with how the P320 RX shoots and what it can do in a match setting.

P320 RX Match Video

Match footage of shooting the P320 RX at the September Quantico Practical Shooters match

Review Summary

As cliché as it is to say, the future is here. Expect that over the next few years optics on pistols will become mainstream and maybe even commonplace. While others may have cracked open the door SIG’s out-of-the-box optics enabled P320 RX has kicked it open and presented the community with an accurate, quality, reliable, and affordable option. At any price point the durability of a slide mounted optic has been the long pole in the tent for this type of platform. SIG’s Romeo1 optic was designed to be durable first and foremost but now that is in the hands of consumers and other end users we will see how it holds up over time.

As of this writing, my RX now has about 2,000 flawless rounds through it. I plan on shooting thousands more through it over the next few months. With the addition of some Grayguns trigger work this is easily my new favorite pistol to shoot. While SIG will no doubt continue to refine both the P320 line and the Romeo1 optic, this setup is good to go now and, yes, you should buy one.

Alma Cole