Sig Sauer MCX Rattler SBR, Discrete PDW – Review

Eli Crane reviews the Sig Sauer MCX Rattler SBR Personal Defense Weapon.

Sig Sauer MCX Rattler SBR
Sig Sauer MCX Rattler SBR

U.S.A.-( I’d like to start off this piece with some background. I don’t consider myself a “gun nerd.” Sure, I own several of them and have spent more time around firearms in the SEAL teams than most humans ever will. However, I don’t find myself daydreaming about various calibers, configurations, and waiting to see what the next cutting- edge weapons system will drop next. I appreciate them, I guess as a lumberjack would a chain saw and grade them on function, features, and usability.

As a consultant/ambassador with SIG, I have got a chance to see much more of the variety the gun industry has to offer at multiple shows over the last couple of years than I ever knew existed outside of the small Naval Special Warfare armory that I grew up in. As the Delta Platoon ordinance rep. from 2007-2010 in Coronado, San Diego. My job was to keep track of, inventory and replace every broken piece of gear we had from optics to NVG’s, firearms, and lasers to name a few. With close to 1,000 pieces of serialized pieces of equipment it was stressful but it taught me a lot about quality gear and I started to learn what was working in the field and what stayed behind when we loaded up the gun cases to get back out on the road training and to redeploy back overseas.

Every once in awhile, I will come across something that I sure do wish we had back in those days. One of the most recent weapons I have come across that would have been helpful and likely fought over by my platoon mates is the SIG MCX Rattler.

Sig Sauer MCX Rattler SBR

Sig Sauer MCX Rattler SBR
Sig Sauer MCX Rattler SBR

For those of you out there who haven’t been brought up to speed yet, I’ll run through my favorite features. I have yet to see a 5.56 PDW (personal defense weapon) as small and compact making it perfect for rapid deployment and CQB. It comes in both 5.56 and also 300 Blackout. The 5.56 measures in at right around 16 inches with its slim, yet sturdy, buttstock folded neatly down its port side. I love that it fits in every backpack I own with plenty of room to spare. It sports a 5.5, inch barrel with a 1:7 twist for the 5.56 and 1:5-inch twist for 300 Blackout. Weighing in at 5.1 lbs. this tiny little thing isn’t going to break your back or be cumbersome loading in and out of vehicles or aircraft. I remember having to issue some of the guys in our platoon MP5 SD’s that were running sources and collecting intel out in town, that had to be able to blend in, small enough to throw into a backpack and yet be capable of getting them out of a bad spot in a hurry. I can guaranty you that had this weapon been available back then our guys would have been carrying this smaller and much more powerful weapon in those situations which is exactly why multiple units within SOCOM have ordered them.

This weapon was actually developed for one of the most renowned special operations units in the world that has been an ally to the United States since the 1940s. I’ll give you a hint, they eat a lot of fish and chips and have a queen.

Since I am not the type of guy who spends hours upon hours tweaking out my guns and gear I want them to be as user friendly as possible so I have time for the more important things in life. This is one real reason I am not the biggest advocate for the M-LOK rail system. Not because it doesn’t work well, it most certainly does. They normally bother me because I’ve lovingly been given the nickname “banana hands” by more than one teammate and I find them difficult and time-consuming to add accessories like vertical grips, lights, and lasers. That is why I was so thrilled to see that on both calibers the M-LOK handguard slid easily off after removing the forward takedown pin, separating the upper from the lower receiver. Which made it so much easier to access and put my Inforce, gen 2 light, and vert grips on them.

Sig Sauer MCX Rattler SBR
Sig Sauer MCX Rattler SBR

I also love the fact that Sig put two QD (quick detachment) holes on each side for attaching various slings onto the left and right sides for right- and left-handed shooters, along with ambi. fire and safety selector switches. I take a lot of friends and family members out to shoot, especially now that the world has gone crazy and people from all walks of life seem more and more concerned with their safety. It is always nice to be able to give someone a firearm to train on that is well thought out to accommodate our differences and preferences.

Now that I have covered a couple of my favorite features let’s get to the good stuff. To start I threw a ROMEO-MSR on the rail system that I picked up at The Hub, gun store in Tucson, AZ. You might expect to have some trouble with accuracy at distance from a 5.56 with a barrel that is the same length as many full, size pistol barrels. To date, I have taken my Rattler out to 150 yards and had zero issues hammering away at my steel silhouettes from Zimco Targets. Last week I even let my twelve-year, old nephew shoot it and he had no problem repeatedly, connecting at 150 yds with the weapon lightly, braced on the bed of my Chevy.

You will notice a little muzzle pressure if you approach someone shooting the 556 from the side. You might also notice that it can be loud and a few readers might want to wear double hearing protection when going hot, especially if you are shooting under a roof or inside. The only thing I don’t like about this weapon is that flash suppressor comes pinned to the barrel to keep you from throwing your favorite can on the end of it.

After reaching out to Sig to ask why I was having trouble removing it, I was told that was done on purpose because the 556 is so hot at that length it would destroy my suppressors after 300 rounds.

I guess there is one trade-off for having that much firepower in that tiny of a package. With the options and features offered and engineering that went into this sweet little thing, you wouldn’t expect it to cheap. Coming in around an MSRP of $2300 it is definitely worth the money for those who don’t skimp with their firearms. Apart from the world of special operations and military uses I can see this weapon being a great fit for hikers, outdoorsmen, and a perfect little ranch gun that will sit nicely on your console while you attend to chores or head to a back-road fishing hole.

Sig Sauer MCX Rattler SBR
Sig Sauer MCX Rattler SBR

If you do get a chance to get your hands on either model of the Rattler. You will instantly get why SOCOM units are ordering them and why an old frogman can’t help but look back and think, “man I wish we had that thing back in the day!”

About Eli CraneEli Crane headshot

Eli Crane is a man of faith, a husband, a father, a veteran, and an entrepreneur.

Eli joined the Navy the week after 9/11. He spent 9 years as a Navy SEAL. After 5 deployments in the Navy, three of them to Iraq he decided to turn the page. You might have seen him and his wife Jen on ABCs hit show Shark Tank where they successfully landed a deal with Mark Cuban and Kevin O’Leary.

Eli is also a brand ambassador for Sig Sauer firearms and a member of the ACVBA (advisory committee veteran business affairs) in Washington DC.

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$2,719.00, uhhhh NO. I can BUILD a duplicate for the $719.00 and save the other two grand for some other “gotta have” weapon or ammo…
No wonder Sig has filed for bankruptcy ! They have overpriced themselves out of existence.


I’ve fired one of the first Rattlers, collapsing brace and all. The brace was awkward for a pistol; it was too straight. The gun was in .300BLK, and was a pleasure to shoot. Unfortunately it belonged to a friend. In a short barrel for personal defense, I prefer the .300BLK.


With that short a barrel, the 5.56 ballistics are going to be WAY below normal. And the noise! To each their own, but I’d prefer a 9mm (or, for 5.56, take the barrel up to 11 inches).