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Sig Sauer Romeo1 vs Romeo3 – Reflex Sight Comparison

The Romeo lineup of sights from Sig Sauer includes red-dot sights with an open design. The lineup consists of, among others, the Romeo 1 and the Romeo 3 reflex sights.

Comparing the Sig Sauer Romeo1 and Romeo3 Red Dot Reflex Sights

As with other reflex sights, they offer better accuracy and almost no parallax than using a scope or iron sights. They also come from a trusted firearms manufacturer.

The company initially focused on the production of shotguns, hunting rifles, and handguns. Sig Sauer only recently expanded its product line, releasing its first optics in 2015.

A few years later, the company released the Romeo line of reflex sights, including the Romeo 1 and the Romeo 3.

The two sights are priced differently and have somewhat comparable features, depending on the configuration. Both choices feature a brilliant red dot for fast target acquisition. You can also adjust the brightness setting. The sight even remembers your last setting after powering it off. The main difference between the two options is the size.

The Romeo 1 is a miniature sight designed to fit most pistols. The Romeo 3 is built for larger guns such as rifles, carbines, shotguns, submachine guns, and full-size handguns. To determine if either option is right for your gun, here is a closer look at the Sig Sauer Romeo 1 vs 3.

Sig Sauer Romeo 1 Reflex Sight
Sig Sauer Romeo 1 Reflex Sight

Sig Sauer Romeo Sights Overview and Technical Specs

The Sig Sauer Romeo family of sights includes eight different sights. The Romeo Zero, 1, and 3 feature open designs while the other options have tube designs.

There are also multiple models of Romeo1 and Romeo3. The standard Romeo 1 has a 30mm lens and is available with a 3 MOA or 6 MOA red dot reticle.

The Romeo 1 Pro is an updated model with a longer runtime. With the standard Romeo 1, you get 5,000 hours of use. The Romeo1PRO version offers a runtime of 20,000 hours and two additional illumination settings for nighttime.

Both Romeo 1 sight models have IPX 7 waterproofing and abrasion-resistant lens coating to shield the lens. The Romeo 1 is ultra-compact, measuring just 44.9 x 32.8 x 27.4mm. It is also a durable choice, thanks to the lightweight, aircraft-grade magnesium housing.

The red dot is clear on the molded glass aspheric lens, including superior light transmission and no distortion for more excellent illumination. You can also adjust the intensity of the dot with the manual illumination controls.

The Romeo3 is a little larger and should fit any Picatinny rail. It weighs 1.4 ounces while the Romeo 1 weighs just 0.8 ounces.

The standard Romeo 3 has a 3 MOA red-dot reticle and an objective lens size of 25mm. The lens is smaller compared to the Romeo 1, offering a slightly smaller field of view (FOV).

Sig Sauer Romeo3 Max
Sig Sauer Romeo3 Max

Several technologies and design features appear on both the Romeo 1 and 3. This includes the MOTAC motion-sensing technology. The MOTAC system conserves battery power and allows for immediate use by sensing motion.

When the sensor detects motion, it powers up the sight. After remaining idle for two minutes, it automatically powers down.

Both models also have the Sig Sauer “infinite guarantee.” An unlimited lifetime guarantee protects the optics.

The Romeo 1 and Romeo 3 are red-dot sights with open designs. While red-dot sights are popular with law enforcement, they are also useful for small game hunting and target shooting.

A person with average skill and familiarity with a pistol can effectively shoot 15 to 30 yards with iron sights (How to shoot with iron sights). The Romeo 1 may boost your accuracy beyond the average range. However, both the Romeo 1 and 3 are sighted for 100 yards.

The Romeo 3 is built for full-size handguns and up, which may include shotguns, rifles, and carbines used for target shooting or hunting. Due to the swiftness of using an open-design red-dot sight, the Romeo 3 can be useful for hunting fast-moving small game such as rabbits, geese, or pheasants. It may also be a good choice for larger game such as deer at 100 yards or less.

Would Sig’s Romeo5 be a good alternative? Check out the review!

Sig Sauer Romeo 3 vs Romeo 1 Comparison

The Sig Sauer Romeo 1 and Romeo 3 are comparable models, as they include many of the same technologies and design features. Both options include motion-sensing technology, high-quality lens coatings, and compact designs for increased stealth.

The Romeo 1 is the smaller of the two. It stands 27.4mm tall, while the Romeo 3 has a height of 42mm when using a low-profile mount.

The smaller sight is intended for use on pistols. It is designed to mount directly to many popular models using mounting plates available from Sig Sauer. However, the Romeo 1 is also available with an M1913 Picatinny mount, allowing you to mount it to larger firearms.

Another difference between the two models is the illumination settings. The standard Romeo 1 sight has ten illumination settings while the Pro version adds two extra nighttime settings. The Romeo 3 has nine daytime illumination settings.

The Romeo 1 also has a larger lens, with an objective lens diameter of 30mm on the standard version. The standard Romeo 3 has a 25mm lens. However, the newer Romeo 3 XL is equipped with a 35mm lens.

A larger objective lens size on a red dot sight provides a broader FOV and provides more illumination. You are more likely to enjoy a clear view and faster target acquisition in low-light situations with a larger lens.

Sig Sauer Romeo1Pro 6 MOA
Sig Sauer Romeo1Pro 6 MOA

What Batteries are used in the Romeo1 or 3?

The Romeo 1 and Romeo 3 sights also use different batteries. The Romeo 1 has a top-loaded CR1632 battery, which has a maximum capacity of 160mAh.

The Romeo 3 uses CR2032 batteries, with an average capacity of 235mAh. The extra power means that you may need to replace the battery less frequently.

Romeo1 Battery Housing

The main advantages of the Romeo 1 include its compact size, wide FOV, and additional illumination setting. However, the Romeo 3 uses batteries that hold more of a charge. Luckily, both options include the MOTAC system to conserve battery life.

What about scope with red dots mounted on top? Which are the best ones?


The Romeo 1 and Romeo 3 red-dot sights from Sig Sauer are closely matched options. However, they are built for different types of firearms.

The smaller Romeo 1 is built for pistols while the Romeo 3 is built for larger firearms. The Romeo 1 mounts directly to SIG 320RX pistols.

Sig Sauer Romeo3 XL 1X35mm
Sig Sauer Romeo3 XL 1X35mm

With the Sig Sauer “handgun adapter pack” mounting plates, it can also mount to almost any pistol on the market, with the exception of some of the most recent pistols such as the P320 X-Five Legion and the P320 X-Compact.

If you are tired of using the iron sights on your pistol and want to upgrade to something that provides better accuracy and target acquisition, the Romeo 1 is a suitable option.

The Romeo 3 is intended for those using larger firearms for short-range shooting, such as target shooting or small game hunting. It mounts to almost any firearm with a Picatinny rail but is not built for pistols.

Keep in mind that you can also mount a Romeo 1 on most shotguns, rifles, and handguns. If you find that the Romeo 3 is too bulky or heavy for your preferences, you may prefer the more compact design of the Romeo 1.

Comparing the Sig Sauer Romeo1 and Romeo3 Red Dot Reflex Sights
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Kevin Collins