The SIG P320 is one of the most popular and well-liked handguns released in the last decade, so much so that the US Military is turning to the SIG P320 as one of their primary sidearms. What about mounting a red dot on one, though?
Many optics-ready models of the P320 are just crying out for a red dot (including the M17 sidearm replacing the M9), but which red dot should you choose?
Don’t worry. We’ve got you covered. We’ve tested several of the most popular pistol red dot sights to find the ones that work best with the P320. Let’s talk about the top performers and go over how to choose the best one to meet your specific needs.
Also Read: How To Use A Red Dot Scope
The Best High-End Red Dot Sights for the SIG P320
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Leupold DeltaPoint Pro
First up, we have our top pick, the Leupold DeltaPoint Pro. This is the optic that the SIG P320s with factory optics cuts are designed to accept without additional mounting plates so that you can bolt the DeltaPoint Pro straight to the slide.
This is much more convenient (not to mention cheaper) than buying an optic that requires an additional plate. Still, it also mounts the optic lower to the bore, dramatically improving shooting characteristics.
The optic will have less “bounce” when looking at the dot, and the gun will be shorter overall and easier to carry.
Mounting concerns aside, though, this is an excellent optic for any pistol red dots. It has an incredibly rugged one-piece aluminum housing wrapped in a steel outer layer and one of the crispest center dots we’ve tested.
It also has an onboard motion sensor that will turn the optic on when needed. It will also turn it off after five minutes of inactivity. Therefore, simply picking up or drawing will reactivate the optic instantly.
Trijicon RMR Dual Illumination
If you’re one of those people who worry about their red dot dying on them when they need it most, I’ve got the perfect optic for you.
The Trijicon red dot sights RMR Dual Illumination uses a combination of fiber optics and tritium to illuminate the center dot…and uses no batteries whatsoever. It’s available in 3 dot sizes (7 and 9 MOA dots and a huge 13 MOA option) and a triangular option that’s great for precision shooting.
The 9 MOA version, it’s worth noting, has been adopted by the US Marine Corps for the SDO and MDO optics programs, so expect to see that one around for years and years to come.
The housing is the same ruggedized aluminum that you’ll find on all other models of the RMR, and the dot is bright enough to see even in direct sunlight. I love the idea of not having to worry about batteries, and I’m betting many of you do.
Many of these optics have batteries that will last thousands of hours, but the tritium in these optics will last a decade, and the fiber optics will last, well, I guess, until you break them, which would take some effort on your part.
Trijicon RMR Dual Illumination
The price of “Trijicon RMR Dual Illumination” varies, so check the latest price at
Also Read: What Is MOA on a Scope?
The Best Mid-Range Red Dot Sights for the SIG P320
Shield Sights RMSC
The Shield Sights Reflex Mini Sight Compact has quickly become one of the most popular handgun red dots around and one of my favorites. The lenses are a nearly unbreakable polycarbonate that is ten times stronger than standard optical glass.
The body is made of ultralight aircraft-grade aluminum, and the dot itself is available in 4 MOA and 8 MOA variants. Hence, you can choose a smaller competition and longer range-focused dot or the larger, more defensively-minded, combat-style dot.
Battery life is between two and three years guaranteed, with an average of more than 4 for an optic that is stored in a dark place. In any lighting, the RMSC will automatically adjust to the appropriate level, or you can adjust it yourself from an NVG-friendly setting to a full daylight mode.
The Best Red Dot Sight for the SIG P320 [Budget-Friendly]
Vortex Viper Red Dot
Next, we have our best bang-for-your-buck pick, the Vortex Optics Viper. The Viper is a highly well-regarded optic that’s been a favorite among pistol shooters for years, and it’s somehow held onto its relatively affordable price despite its popularity and success.
You have to either start with a blank P320 slide and have it milled, order a specially milled slide, or use an adapter plate with one of the optics-ready models that come cut from the factory. Other than that, the Viper is a perfect option for the P320.
It’s lightweight, very low-profile, and waterproof, so you don’t have to worry about getting caught in the rain. Vortex also has some of the best lens coatings in the industry, so the view through the glass is clear, bright, and relatively color-accurate.
This is one of the market’s most affordable pistol-ready red dots, and Vortex’s industry-leading lifetime warranty backs it up. Therefore, you can be sure that, despite the relatively low cost of entry, Vortex will always stand behind its product.
Also Read: Vortex Venom vs Viper
Holosun HS570K X2
Next up, we have another one of my favorites that you’ll find on a few guns in my collection, the HOLOSUN HS507K-X2. This is one of the most versatile optics on this list, thanks to the multi-reticle system.
The MRS system allows you to choose between a 2 MOA center dot, a 32 MOA circle, or the dot and circle together, similar to an EOTech holosight. This gives the shooter an immense amount of choice depending on what type of shooting you’re doing.
The dot-in-circle is a familiar option for me, and that’s what I use. The large ring to get a sight picture quickly and the small 2 MOA center dot to allow for precise aiming make for a very easy-to-use optic.
Beyond that, you get an automatic off, shake awake, and a lock-out mode to ensure the optic doesn’t get turned on when not in use and a holster or case. Finally, the battery door slides out of the rear, so you don’t need to unmount the light once your 50,000 hours of run time are up.
Burris FastFire 3
Lastly, we have another one of my personal favorites, the Burris FastFire3. Burris broke into the world of red dots a few years ago with the original FastFire, and the latest version combines an excellent feature set with an extremely attractive price point.
It comes with the option of a 3 MOA or 8 MOA dot, depending on the version you go with, and both models come with an automatic brightness sensor to adjust the dot to the ideal setting in any light conditions. You also have three manual brightness settings if you want to set things yourself.
Burris measured the estimated battery life at around five years between the auto brightness and the automatic shut-off after 8 hours. Even when you do have to change the battery half a decade or so from now, the fact that the battery door is top-leading means you don’t have to unmount the sight.
Finally, Burris has some factory-ready mounting plates that you can use to mount the FastFire 3 quickly and easily, without a lot of hunting for extra screws and a specific adapter plate.
Buying Guide
Budget
Your budget is one of the most essential considerations when selecting a red dot for your Sig P320. Red dot sights are available at a huge range of price points, and it’s a good idea to have a budget you’re comfortable with before diving into your options too much.
Dot Size
Another important consideration is the size of the dot. The smaller the dot, the less of the target it covers, allowing for more precise aiming. On the other hand, the larger the dot, the easier it is to see, allowing for faster target acquisition.
Since pistols like the Sig P320 are typically used at closer range, you’ll generally want a dot that measures at least 4 MOA, but 6 MOA or larger would be even better.
Brightness Settings
Generally, red dot sights feature a number of brightness settings for you to choose from or have automatic brightness that adapts to the amount of ambient light. Some sights have both.
Neither option is bad. The right one for you just depends on whether you’d like the extra level of control of your reticle’s brightness or prefer not to have to worry about it.
Battery & Battery Life
Red dots require a battery, usually a CR2032 or CR1632, which does not make much of a difference for the things you’ll care about when buying a red dot. However, sometimes red dots will use a different type of battery, which makes more of a difference.
A larger battery means that the sight needs to be larger. Some battery types are more expensive or difficult to find. Fortunately, red dots tend to have a long battery life, making replacement a pretty infrequent issue. If a sight has features like motion sensing and automatic shutoff, that extends the battery life even more.
Durability
Investing in a sight that can stand up to just about anything that’s likely to get thrown at it is a good idea. Even if it’s more expensive, you’ll still come out ahead compared to re-purchasing cheap, flimsy sights over and over again because they keep falling apart on you.
Look for a red dot reflex sight that’s at least waterproof and shockproof. Scratch-resistant coating on the lenses is also convenient for protecting your optics. A hard-anodized or Cerakote finish will also protect the sight’s housing from scuffs and scratches.
Speaking of the housing, make sure it’s made from a rugged material, like aluminum.
Mounting Plate
Because of the variety of pistols and red dots on the market, every red dot is not guaranteed to mount directly on every pistol. It’s not the end of the world if your preferred red dot won’t mount directly onto your P320, though.
You can almost always get a mounting plate that will act as an adapter for just a few extra dollars.
FAQs
Though some may need an adapter plate, most pistol-style micro red dot can be mounted on the SIG P320. The Delta Point Pro and others with the same footprint can go right on the M17, M18, and XFIVE Legion.
The SIG P320 M17 is cut for the same optic pattern as the US Military’s MHS contract requirements, which is more commonly the Delta Point Pro format. Any optic with this mounting format can go on without an additional plate.
Final Thoughts
There are a lot of great red dots out there that will play nicely with your SIG P320, but these are the best ones around. We’ve tested and abused these optics, and while many didn’t make the cut, all the choices on this passed with flying colors.
Our top pick overall is still the DeltaPoint Pro because that’s the red dot that the optics-ready P320 models are specifically designed to fit. Still, even if you choose a different option, all it takes is a simple mounting plate, and you’ll be ready to go.
The only thing you really have to worry about is which one you like the most.
