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  • Post last modified:March 21, 2023

Rattler MCX with Sig ROMEO4S

Referenced Copsgunshop.net

The 5.5″ barrel Rattler MCX is designed for 300 AAC Blackout, with an effective range up to 100 yards, but definitely not past 150 to 200 even using supersonic 300 BLK ammo un-suppressed.

It's definitely a CQB gun and you can use any optic, but the best optic for Sig Sauer Rattle MCX that we recommend is low profile ones that fit the PDW profile.

In particular the Sig Sauer ROMEO4S has a great price point & quality similar to an Aimpoint Micro.

Honestly, you can go with anything you want, but I want to show you the other 3 low profile size optics for the Sig Rattler.

Let's do it!

5 Best Optics for Sig Sauer MCX Rattler 

The Rattler is a innovative design based off the Sig MCX, and this gun is purely designed from the ground up to be a compact micro size gun optimized for 300 Blackout suppressor use when using subsonic ammo.

It's designed to be thin, durable and discrete, therefore keeping it minimalistic is important. A non-magnified optic like a red dot sight with large field of view is the best option for:

  • Weight savings
  • Faster weapon maneuverability
  • Streamline weapon profile without snagging on clothes or belt
  • Easier concealment in backpacks, under the jackets & in vehicles
  • Effective enough for close range engagement
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Check out more: Best PCC (Pistol Caliber Carbine) Red Dot Sights

Sig Rattler PDW Needs Compact Size Red Dot Sight For Speed

Sig MCX Rattler ROMEO4S

Image Referenced Tactical-Life

Everything about the Sig Sauer Rattler MCX is about speed and compactness. Having a small optic size that doesn't increase the vertical body profile of the gun helps the user to conceal or store the gun better.

A large profile sight like the with flip-up lens cap or other external features have the possibility of getting snagged on things when drawing from concealment.

This applies to Rattler MCX pistol as well.

MUST Have Shooting Accessory When Using The MCX Rattler


The MCX Rattler produces a lot of gas especially when it's suppressed, and all of the gas hits the shooter in the face causing watering in the eyes.

This prevents the shooter from seeing clearly through the red dot sight. Most people who understand and own the Rattler MCX use the gun with a suppressor for noise cancelling.

Even though safety glasses can't completely block the gas from hitting your eyes, but it will help.

What Optic Reticle To Use For 300 BLK At CQB Distances

A 2 or 3 MOA dot size optic with a reticle ring is the best choice because it gives the shooter the optimal aiming performance for CQB & holdover reference points for long distance shots.

Here is why:

The 300 Blackout round is optimized for a 9″ barrel, but the Sig Rattler only has 5.5″ long barrel, and it can reach about 100 yards with a muzzle velocity on average 1800 fps & 900 ft-lb energy while using 125 gr supersonic ammo.

When using 200 gr subsonic ammo – the muzzle velocity is about 850 fps & 310 ft-lb energy.

As you can imagine the round fired will lose much more energy as it goes down range. In another word, this gun shoots like a 9mm but with a much heavier bullet.

What Distance To Zero Optic On Sig MCX Rattler?

The best zeroing distance for the Sig MCX Rattler is between 15 to 100 yards with a 3-4″ shot group. Anything past 150 or 200 yards the bullet drop is significant.

So when you zero your red dot optic for the Rattler, please zero it with the purpose of CQB PDW use only.

Wrap Up

Sig Sauer designed the Rattler MCX to be compact and suppressor optimized using the 300 blackout cartridge. It's accuracy and firepower is close to a heavy grain 9mm but much bigger bullet, much more muzzle velocity and energy.

The gun is accurate up to 100 yards, and the best optic we recommend is the Sig ROMEO4S for its the price and quality. Of course you can pick other optic of your choice, but for the price & quality the ROMEO4S is it for the Rattler.

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