Rat Worx MRX Knife – Tactical Auto With Style

Rat Worx has been making innovative firearms accessories since being founded in 2002. Headquartered in Mt. Morris, IL they are known for high quality accessories for firearms ranging from Microtech MSAR’s to M3 Grease Guns, and now they’ve teamed up with Guardian Tactical and turned their engineering genius and penchant for quality towards knives.

Rat Worx MRX chain

The first feature to grab my attention was the miniature motorcycle chain wrapped around the front of the MRX.

While perusing the booths at this years Bullpup Shoot held in Park City, KY I took notice of a very unique looking knife laying on the Rax Worx table. The feature that jumped out and grabbed me was what appeared to be a miniature motorcycle chain integrated into the otherwise conventional looking knife. I knew from a glance the knife laying before me was an automatic and the presence of the chain prompted an involuntary movement; it leaped into my hands.

My first task was to figure out how the chain was used to open the blade. To begin my investigation I first had to press the release button. Upon doing so, the hearty 3.5″ blade flung open with more authority than other side-opening automatics I’ve used in the past. It was obvious to me that the chain was pulling the blade from its perch and continued to apply spring tension throughout its movement. What wasn’t obvious from examining the knife is how it all worked internally, so I asked.

Rat Worx MRX

The MRX is 8.5″ in length extended and is an attractive knife.

Hidden inside the knife there are two nested right and left hand wound extension springs. These work in concert to pull the miniature roller chain which in turn applies ample force for a positive blade opening. The blade pivots on a permanently lubricated ceramic ball bearing washer system which contributes to the smooth operation and durability of the design.

The blade is .155″ thick, is made from 154 CM steel with a RC hardness of 58 and is machine hollow ground. 154 CM is an American made high carbon stainless steel that provides for good edge retention and is a good choice for heavier cutting applications. It was originally designed for jet engine fan blades and was a precursor to the Japanese made ATS-34, another popular blade material.

Folded the knife is almost exactly 5″ in length and opened it is 8.5″. The handle is .5″ wide and the release/lock button is recessed yet allows for easy indexing and opening of the blade. To open the blade you simply push the release button. To fold the blade, you again depress the button and fold the blade back into the handle. The pocket clip is located on the right side of the handle and the button is on the left side, so it’s safe to say the knife favors right hand use.

Rat Worx MRX

In the hand the MRX is comfortable and easy to use. I prefer the drop point blade over the Tanto style which is also offered.

The handle is made from 6061 aluminum that is class III hard coat anodized leaving it with a tough black finish that seems to hold up well. I find that the knife fits well into my large hands and is comfortable to hold and use. Another interesting feature is that all markings are tucked nicely away inside the knife handle and are only visible with the blade in the open position. This leaves the knife looking very clean.

The MRX can be had with either a drop point blade or a Tanto style blade. There are currently three different blade finishes available as well; black, bead blasted and two-tone. I opted for the all black drop point knife, however if they would have had a bead blasted drop point on the table I would have likely taken it home with me.

When you pick up the MRX and fiddle with it, you’ll find that the knife has zero play anywhere. With the blade extended you can apply ample pressure side-to-side and you’ll discover there is absolutely no discernible¬†wiggle. Despite being a production knife, it feels extremely solid and it gives you the impression of being a custom made blade. The MRX is 100% American made and features a lifetime warranty.

Rax Worx MRX markings

The markings are tucked away inside of the handle and are only visible with the blade open. You can see my knife is serial number 50. (click to enlarge)

I asked about the durability of the knife and was told that in testing it had handled 418,000 cycles without a failure. Wow, that is impressive. However, in looking at the knife and playing with it endlessly for the last two days I can believe it.

So, what do I think of it? I freaking LOVE this knife. It stands out. It makes a bold statement. It’s ergonomic and seems to be built like a tank. There’s nothing else like it on the market.

My state (Indiana) legalized automatic knives this past July, so I’ve been kicking the tires of many different makes and models. I tend to gravitate towards “out the front” (OTF) knives, at least initially, because of the fun factor. I realize they’re not nearly as robust as a good side folder like the MRX, but I still have a thing for them. The unconventional design of the MRX changed that, I couldn’t get the credit card out fast enough after having an opportunity to play with it at the Rat Worx booth. It really is that cool, at least for me.

The MRX is currently available on the Rat Worx website and retails for $325.

If your state allows for legal ownership of automatic knifes and you’re looking for something different, I recommend you check out the Rat Worx MRX. I don’t think you’ll be disappointed. The MRX has moved up to my daily carry blade so I will keep you guys posted how the knife holds up.


MAC is an avid shooter, former MCSF Marine, NRA member, Oath Keeper and is commissioned as a Colonel by the Governor of Kentucky. Known for his videos on the Military Arms Channel, he also writes for The Bang Switch, for Shotgun News (Be Ready!) and freelances for Guns & Ammo. MAC has been a life long shooter who has an interest in all things that go "bang" but gravitates towards military type firearms.

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  • http://gravatar.com/jnazari jnazari

    Too expensive.

    • Jay

      A good knife costs some money. Have a few Microtech Blades and they work great. Spending $200-$300 is not bad but $1000 or more for something I can’t shoot is a little much for me;)

      • Rafael Paulino

        You’re not kiddin’. I’m dieing to get my hands on a Microtech Combat Troodon. The full size but it gets a little expensive & I just don’t want to settle for just any blade. I want what I want. I’ll get it someday…

    • http://www.btls.us Jestik

      I’ll put my $25 RAT 1 or Spyderco Tenacious or Kershaw Skyline up against your $200-300 knife and we’ll see if you really get the +$175-275 you paid for it.

  • http://www.Range5.com George Hill

    Yup until my relocation to NC, I used to ride about 8,000 miles a year on motorcycles.
    Chains stretch, you gotta adjust, clean, and lube them every 600 miles or less depending… just a huge maintenance hassle. I was cleaning and adjusting every Saturday.
    I’m not sure I want that on my knife… Adjusting every 600 flicks… chain lube dripping on my pockets… Are they X-Ring chains at least?

    • http://www.military-arms.com MAC

      I would say a motorcycle chain has a wee-bit more stress placed on it than this knife.

    • http://www.maticorearms.com Sven J

      Ratworx has tested the knife to 418,000 operation cycles before it finally failed- that is between 10 and 20 times what your typical auto folder is designed to handle. You can see some videos of the testing rig on Youtube.

      There is no issue with the chain- even if it was to stretch the double nested springs are going to take up the slack. Comparing a motorcycle drive chain to the MRX knife chain is apples to oranges.

  • booker

    Looks like a mini bicycle chain.. and a lint trap. Cool design though, certainly a conversation piece.

    • http://www.military-arms.com MAC

      It’s more than a conversation piece, it’s a fully functional knife. But yes, it’s a neat way for you to make a bit of a fashion statement.

      As for lint, if you find a lint free knife please let me know. All of my auto’s collect lint. I can’t see how lint would be any more detrimental to this knife over my OTF Infidel. This knife clearly has more spring pressure to overcome lint than the Infidel.

      • booker

        I’m sure it’s functional, for $300+ auto or not, it better be functional. I wouldn’t expect a poor product from Rat Worx anyway, they put out great kit. What’s your take on the profile and the grind? I must say I like the way the belly of that drop-point blade looks, almost reminds me of a nessmuk blade. Great utility and general purpose knife design. How sharp was it out of the box?

        I haven’t found a lint-free folder yet, but working on it. My point was that with the chain, there appears to be about ten little holes for lint to collect inside and then to potentially be pulled into the mechanism. Time will tell, it’s a cool piece regardless.

  • Steve

    $325 for a pocket knife? What do you guys smoke up there?

    • http://www.military-arms.com MAC

      If you think $325 is exorbitant for an automatic, don’t follow this link as you’ll likely have a heart attack.


      • Colby

        Don’t tell me what to do!….[CLICK].

        Several glycerine pills later, I realized you were right and lamented my prideful rebelliousness.

  • Josh B

    I was all interested and about to go looking for one just for the cool factor until I saw the price. Then I pooped myself a little.

  • http://gravatar.com/kperryman777 Kevin Perryman

    One would have to carry it for a month or two to see if it works as one might initially believe. Ge back to us, willya?

    • http://www.military-arms.com MAC

      That’s the plan, hence the last sentence in the post. :)

  • Operation_orange

    Still love my Emerson CQC-15. Everything under the sun is prohibited here in Canada. Thankful for eBay.

  • Samuel Suggs

    What happens when one of those tiny little links smashes into a rock breaking it? Do I then have a spring unassisted flipper or what? You know I always wanted a vital part of the operation of my automatic knife to be exposed to breakage, grit and dirt human error so it could have slightly more leverage on the blade and open with a more satisfying snap cuz you know that gonna scar the bad guy away right ;)

  • Rich Nixon

    I recently bought *something* from RAT WORX and had a very pleasant experience.
    You may or may not like the knife but consider supporting them as they are located in the Peoples Republic of Illinois.

  • Dreamour

    I’d buy it for $32. NEVER is a knife worth it for function at $325. As a “collectors” knife for investment to be stored .. maybe.

    • http://www.military-arms.com MAC

      There are a lot of knife people that would disagree with you. Sure, some guys buy $30 knives at Walmart and they serve them well. You can also buy a Hi Point pistol and it will likely serve you just as well.

      Others will prefer high-end knives and guns.

      $300 isn’t an outrageous price to guys into knives just as $1,500 isn’t considered to be a lot of money for a decent 1911 pistol.

      • Jay

        What is expensive to one person is not bad for another. I just picked up a “PS90 exploded view” poster off GunBroker for $120 because I liked it and couldn’t find one until now. Was told I was dumb for that, but I really wanted it. To each his own.

        • Jon

          I agree, everybody is into something that to others seems frivolous. People drop ridiculous amounts of money on shoes or clothes when the same item in a different brand will cover your naked body equally well for a fraction of the cost. A Yugo will get you from point A to B but a Ferrari makes the same drive completely different. I can cut things with a $20 knife but this knife, to me and my blade loving friends is worth every bit of the $325.

  • http://www.youtube.com/channel/UCIPNHdOgSxlhMXWeoUMdiUw/videos Hawaii Volcano Squad

    Karambit are the best self defense knife bar none if you know how to use them, and at close range, faster than a gun if you have the Emerson wave type.

    Honestly MORE IMPORTANTLY though right now in my town, primary internet has been DOWN since Friday or Saturday and Kona, Hawaii is a DEAD cash only town! No Credit Card processing no cellphone, no internet cloud for major businesses that rely on them for EVERYTHING. I wasn’t a prepper before this but wow this is insane. I posted video about this on my youtube, but I assure you this is real. Hope it gets fixed soon, this town is a mess.


  • Dustin

    Not an emerson. Can not do it thanks mac for getting me stuck ok them! Emerson that is

  • Austin

    I’m trying to justify buying a benchmade, Piranha, or Microtech OTF knife. Are they really that practical or useful even, or am I just better off picking up another waved blade?

    • http://www.military-arms.com MAC

      I wouldn’t use an OTF for self defense, they’re too frail and unreliable in my personal experience. I love OTF knives, but I use them for utility knives.

  • http://www.youtube.com/channel/UCIPNHdOgSxlhMXWeoUMdiUw/videos Hawaii Volcano Squad

    Prefer Fox knives version? Main thing is the patented wave notch hooks on you clothes as you take it out of your pocket and so deploys automatically as you draw it. FAST!

  • Brent

    I have a spyderco for around $100 and it lasted over 10 yrs, have a schrade auto for $60 and its a great knife. No way I’m paying $325 for a pocket knife unless it has diamonds in it.

  • otis

    saw on the website they listed the blade as CPM 154 and 154cm… minor differebce, but i wonder which one it is?

    • http://www.military-arms.com MAC

      My blade is stamped 154CM.

  • Pingback: A New Type of Auto!! - Page 3()

  • Steve

    Whats with all the haters? Lol.
    Coming from a fellow knife lover, that’s an awesome blade. Very unique. Good choice Mac.

  • http://gravatar.com/gipbmac Tom McIntyre

    I like this knife! It’s cool – and paired with a Harley owner it would be perfect! ;) It looks very well made – very business like – Sparta meets the Industrial age.. I want one!

  • Don Marcellino

    I am looking forward to receiving a tanto two-tone; though my only worry is the kit. How can I receive one already built? I am not a knife builder and I want to make sure mine is assembled by a professional. (Not me) so before I buy one I need to know; can I receive one built?