Ruger SR-556 Takedown Update


Ruger released an update to the company’s SR-556 Takedown rifle. The new Takedown gun replaces the quad rail forend with a KeyMod model. The result is a gun that is 1/2 a pound lighter. The original gun weighed 7.6 pounds while the new gun weighs only 7.1 pounds. Additionally, the front end of the rifle is thinner, which may make it easier for some shooters to hold.


I recently had a SR-556 Takedown for review and found the gun was a bit front end heavy. I like the idea of going to an alternative accessory rail like the KeyMod to lighten the load and shift the gun balance farther back.

The Takedown gun is designed to allow the barrel to be removed by pulling down on a tab and twisting the barrel to unlock it. Broken down in this way, the gun can be stored in a smaller package than just removing the upper from the lower. Additionally, a shooter can install a 300 BLK barrel and run a .30 caliber cartridge from the same package.


Concerns about maintaining zero with an optic when removing the barrel are reasonable. If you are shooting with the iron sights, all of the adjustments are made to the front sight, which is attached to the barrel. In my testing, I found the iron sights kept zero when swapping barrels back and forth.

Richard Johnson

An advocate of gun proliferation zones, Richard is a long time shooter, former cop and internet entrepreneur. Among the many places he calls home is


  • Seamus Bradley

    Looks like a very nice rifle. Any word on the price point for a separate barrel?

  • DIR911911 .

    wasn’t quite sure why an AR would need to be even smaller when taken apart , but the barrel change option looks interesting. possibly a chance to pick up where the acr fell short.

    • Twilight sparkle

      No guns seem to have done that, well at least not at a reasonable price, the barrel change kit usually cost more than just getting a new gun.

      • CavScout

        Mostly false. The LMT MRP. It’s generally how the SCAR, ACR, and others should have been done.

        • Twilight sparkle

          How is that a reasonable price at all? For the price of the barrel and piston assembly you could just build an ar.

  • Evan

    I don’t get why anyone would want nonsense like KeyMod and M-Lok instead of quad rail. It saves a negligible amount of weight, and in doing so gives you a crummy proprietary system for mounting accessories instead of something universal and battle proven. I get that most people, myself included, are never going to use every bit of rail space. Still, it’s nice to have it there. The whole point of rails is modularity, and these new fads do nothing but reduce modularity and convenience in the name of saving three ounces on a 7lb rifle.

    • Vitsaus

      M-Lok is debatable, but Keymod has beeen adopted by the majority of high-end brands, as well as a number of middle of the road, and a few low-end makers as well. The weight savings is in fact noticeable, and often times you can add an optic for the same total weight your old set up had with out on. It has equal (if not more) modularity than a a four sided quad rail as many Keymod rails have between 5-7 usable sides not counting the top side pic rail most of them have. Not to be condescending, but I used to think just like you about a year ago until I started using Keymod and I really can’t go back to traditional quad rails now.

      • Evan

        OK, I’ll give you the 5-7 sides, but still, the fact remains, for many if not most accessories, you still need to get a piece of rail, attach that, and then attach the flashlight or whatever to the rail. That is not a desirable feature to me. The good thing about quad rails is that they’re universal. I can take literally any accessory made in the last 15 years or so and attach it to my quad rail with no extra step. I can then take it off and put it on any other rifle I choose. I’ll admit I never used Keymod and don’t quite know how it works, but based on pictures and assumption, it seems like a less secure way of attaching accessories, too. I just don’t see any advantages.

        • Laserbait

          “I’ll admit I never used Keymod and don’t quite know how it works, but
          based on pictures and assumption, it seems like a less secure way of
          attaching accessories, too. I just don’t see any advantages.”

          Really!? You made an ASSumption, without any working knowledge of Keymod, then proclaim it to be inferior? The internets are strong with this one…

          Do your self a favor, try a Keymod or MLok AR15 before making more assumptions, you’ll look less ignorant.

          • Evan

            If, based on pictures, the way Keymod accessories attach is intuitive, it isn’t as good as the way accessories attach to rails. If this were not the case, I suspect we would see a lot more 12 o’clock rails switched to Keymod. It would certainly be possible, if harder to manufacture.

          • nadnerbus

            top rails require precise alignment for optics irons and other sighting devices. Pretty much everything mounted to side and bottom rails doesn’t need to be as perfectly aligned.

        • nadnerbus

          Couldn’t disagree more. Keymod/M Lock give the best of both worlds with regard to smooth free float hand guards and quad rails. You have the option of keeping it clean, and just using it as a traditional hand guard, or adding accessories as needed without adding weight and girth.

          Lets be real. How many people are really using even a quarter of their rail real estate, much less moving accessories to different locations very often. For non military, you might have a VFG or AFG, light on a side mount, and MAYBE a laser. You don’t need 90 % of the rail space for that. Even military probably won’t need more, since IR lasers/illuminators usually go on the top rail these days.

    • Kelly Jackson

      I don’t like all of these odd variants either, but a half pound is more than negligible.

      • Evan

        I thought it said five ounces. I just reread it, and you’re right, it did say half a pound. Either way. I’ll take the extra half pound. It isn’t all that much.

    • hking

      Rails are big and bulky in addition of weighing more, they need rail covers to be comfortable and to avoid snagging and scraping, which adds more weight and bulk. A negative space attachment system allows for a much more compact and streamlined handguard with a much smaller ID and OD and for attachments to sit closer and flush to the surface of the handguard. Also better heat dissipation via more ventilation openings.

      • Evan

        I’ve shot with many different rails, on both military and civilian rifles, and I have never once considered a quad rail big or bulky. I don’t have a problem with them causing discomfort either, especially with a Magpul AFG. Your point about heat dissipation is valid, but outweighed by all the other negatives of Keymod v. quad rail.

        • hking

          As a user of quad rails on 6 rifles ranging from SBR’s to SPR’s for the past 10 years, switching to all Keymod was a easy decision. After going with something better you really see the shortcoming of the old platform. I really dont see any advantage of a rail interface versus keymod having been an extensive user of both platforms. Any accessory you could ever want is available in mlok or keymod as well. People complained that no magpul crap was keymod, but they found other companies making much better products to do the same thing.

    • Laserbait

      8 ounces that far away from your shoulder makes a bigger difference than 8 ounces in the buttstock, when it comes to holding a rifle on target offhand for a long duration.

      I think this is a great upgrade!

      • Evan

        Weight, like most things as far as guns are concerned, is a compromise. I’d much rather have a 10lb rifle that did everything I wanted it to than a 5lb rifle that had to omit features I want. A half pound of weight isn’t enough to compensate for the fact that Keymod is an inferior system.

        • Laserbait

          What fact? You have no working knowledge of Keymod – you said so yourself.

        • Doug73

          Evan, you remind me of a famous Mark Twain quote: “It ain’t what you don’t know that gets you into trouble. It’s what you know for certain, that just ain’t so.”

          This is a problem in America these days. People all too often think their own beliefs are “facts” simply by virtue of those beliefs being their own. These people think that merely having an opinion on something, is itself sufficient to make their opinion “fact”. Unfortunately for your argument Evan, that isn’t the way the world actually works.

          Moreover, saying its a “fact” that Keymod is inferior when you freely admit you have absolutely no experience with it, strikes something of a death blow to your credibility on the topic. Please tell me you understand that, right?

          • Evan

            What an ironic comment.

            I said I don’t know exactly how accessories attach with Keymod, though I assume it’s pretty intuitive based on how it looks. Either way, it’s clearly inferior because it’s essentially a proprietary system which offers no distinct advantage over quad rail, and still requires rails to be attached to work with many if not most accessories. You really can’t argue against that; it is objectively true. Basically, you prefer saving a few ounces over function. I do not. Function comes first; then other considerations like weight can be addressed. Quad rail functions perfectly, and can be used for anything from bipods to lights to PEQ-whatevers to M203 grenade launchers. Keymod is not nearly so versatile. It’s an answer to a question nobody asked, and because you choose to jump on this fad does not make it equal, much less superior, to a proven and unflawed system.

    • NDS

      Run a rifle hard with an uncovered quad-rail handguard and you will cut yourself, snag clothing, have a generally hard time. Most quad rails are ran covered for this reason, so not only do you have a heavier, larger diameter rail, you must account for the weight of ladders or other types of covers.

      I’ll agree that at it’s introduction picatinny railed handguards were a game-changer and indeed “battle-proven”… but now that there is something better why not adapt to the times? Do you still use a wooden stock because a synthetic saves a “negligible” amount of weight?

      I did not change to the Key-Mod system at it’s start as adding picatinny rail segments to attach accessories seemed ridiculous to me. Now many accessories attach directly to the rail.

      • Evan

        In Iraq, I ran my quad rail with no covers, no gloves for the first half of my deployment until they made it a rule, and didn’t once snag gear or hurt myself in any way. If you’re having those issues, I imagine you’re using cheap, poorly made gear. Quad rail is a good system, but that isn’t to say that poorly made examples don’t exist.


        • JK

          I’ll admit that I don’t run my gear hard at all, but I’ve yet to cut my hand or snag my gear on my UTG Pro quad rail. Maybe I need to spend a few more dollars to get the sharp, unfinished edges and burrs that seem so prevalent on the higher end systems the experts talk about.

    • C77A1

      Both M-Lok and Keymod provide a return-to-zero mounting solution which remains exceptionally rugged; moreover they also allow for FAR cheaper production, weight savings, a lower-profile handguard, and inherent ventilation; what’s not to like? When the mounting market fully catches up with the new mounting options, I personally see quad-rails going the way of the dinosaur; aside from extant tooling and user familiarity, there’s really nothing they add that the new options don’t.

  • Austin

    What’s interesting is that Ruger has removed the links to all models of the SR-556 except the takedown from their site. Have they discontinued the other versions, or can we expect to see updated ones in the near future?