5.56 NATO vs 223 Remington

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16 Responses to 5.56 NATO vs 223 Remington

  1. SemperFi, 0321 says:

    Just splitting hairs, nothing more. People will argue all day long that they’re not the same round, true, they do have different specs, but nothing that will prevent one from being fired in another. And do you really think that 52,00 CUP will blow up in a rifle chambered for 50,000 CUP?
    Match target chambers are one thing, but the average shooter will never tell the difference between his .223 AR-15 and a 5.56 M-16. I know some bolt actions are too tight to chamber a 5.56 FMJ, so don’t use it!!!
    Sorry, but most of the difference is from the fact that Remington could not take the exact US Gov’t 5.56 blueprint and copy it, they had to change some of the neck specs, just like Winchester did with the .308 Win/7.62 NATO. They would have been busted for copyright infringement. So that’s where you get the variance in specs.
    Even the US Gov’t does not make an issue of the slight differences, I have had in my own possession brand new factory loaded SAW belts loaded with brand new Fed .223 brass, and recovered gov’t MG brass with civilian headstamps (.223 Rem) and NATO headstamps, so WTF?
    I trim all my brass to 1.750″ length, load per M-193 specs and call it good. I’ve been shooting many different .223/5.56 weapons for 42 yrs now, haven’t seen one blow up yet!
    Just my .02 cents worth, YMMV.

    I think you should be more concerned about what twist rate ( 1/12, 1/9, 1/7 ) you have vs. your bullet weight, that can really screw up your accuracy, or lack thereof.

    • Wirecutter says:

      Agreed. I think the only Mini-14 that you can’t shoot 5.56 from is the target model because the tolerances are too tight. But other than that one and probably a bunch of bolt guns chambered for 223, you’re good to go with either caliber in damned near every rifle made.
      Rate of twist is everything when it comes to bullet weights and accuracy. Most folks will say that their 308 (as an example) shoots 150 grain bullets real well but accuracy ain’t shit shooting 180s. Rate of twist is why. If they were to check with everybody shooting the same model and barrel they’d find out that everybody else is having the same bitch.

  2. singlestack says:

    When I saw this I thought, ” Ah shit, is that old chestnut back?”
    The worry about NATO ammo blowing up Remington chambers has been debunked for a long time, both by scientific testing and by sending millions of rounds downrange.
    If you want to worry about kabooming a rifle start fucking with the 300Blackout and don’t be meticulous about not letting it get mixed up with your .223. Stick with .223/5.56 and you’re good to go.


    • SemperFi, 0321 says:

      Excellent write-up from luckygunner, everyone should read and post this.
      There are also a lot of gun people who try to make money off your ignorance and sell you another rifle/barrel you really don’t need. That’s why the myth keeps perpetuating itself.
      So the next time someone tries to tell you you’ll blow your face off, it’s because
      1. he doesn’t understand it himself, or
      2. he’s trying to be a fukn know-it-all
      3. he’s trying to scam you into buying something.

      And if you find a chamber too tight to close, don’t pull the trigger. Use something else. I’ve seen plenty of surplus bolt guns that the same rules apply to also. Not every cartridge fits every chamber.

      • Wirecutter says:

        Who the fuck would try to fire a round when the chamber won’t close completely?

        • SemperFi, 0321 says:

          The world is full of Darwin Award applicants.

        • SemperFi, 0321 says:

          OK, here’s an example from my memory bank.
          I worked with an old gunsmith 30 yrs ago, he told me of a Remington 700 .270 Win. bolt gun some guy brought in, all busted up and the scope was dented in the middle. Bolt would not open and the bore was plugged. Dick took it apart, applied heat and a hammer to the bolt handle until it slowly opened. Chamber was full of brass particles and the bolt face still held the remnants of a case head, a ,308 Win. case head!
          It appears the owner was out hunting with a buddy in his pickup truck and spotted a coyote in the distance. He stuck his rifle out the window and discovered the rifle was empty, so he reached to the middle of the seat and grabbed a cartridge from a box, slid it in the chamber and closed the bolt. He pulled the trigger and knocked his ass out cold! The rifle recoilled so hard it hit the top of the window frame and bent the scope, and his buddies .308 cartridge seized up the entire action, after blowing out the primer hole and down the mag well and plugging the bore. Wanna take a guess what the chamber pressure was???? That Remington action held together, barely.
          Stupid shit happens!

          • singlestack says:

            I have a friend who collects Arisaka rifles. He also has several 98 Mausers in 8 mm.
            One day while shooting a Type 99 (7.7 mm) he didn’t realize a Mauser cartridge had somehow gotten into his ammo bag and he didn’t notice it when he loaded it into the Arisaka. He fired it and the tremendous recoil made him realize something was wrong. There was no external sign of any problem and he opened the bolt, which was a little stiff. As soon as he saw the case he knew what had happened.
            The rifle was completely undamaged and he still shoots it..

        • singlestack says:

          There are some rifles that will fire in an out of battery condition and there have been documented cases of people pulling the trigger on unlocked guns, often with fatal consequences.
          Slam firing is an inherent danger with service rifles (M1 Garand, M14/M1A, M16/AR15, AK47/74, SKS) due to their floating firing pins. If you handload and don’t use hard primers made for service rifles and your rifle is even slightly out of time you run a very high risk of an out of battery slam fire.

        • anonymous says:

          Sometimes, it sneaks up on you when you aren’t paying attention. Some years back, we were at the ranch shooting off a bench when I began having trouble closing my Ruger M77 6mm Remington (Federal Premium) – bolt wouldn’t close on the round. So I pull it out to find its a .270 Winchester round.

          ??? WTF – I don’t even OWN a .270 Winchester.

          How this happened – we were taking turns shooting to reduce barrel heating up. The previous shooter had shot his rifle (.270) and after unloading his unspent, placed the .270 into my cartridge slide same Federal, different round.

          Complete dumbassery on both our parts, he for inserting wrong ammo, me for leaving my ammo slide on the table allowing that possibility.

  3. Steven says:

    I’ll never get that time back. That BOY reads too much interweb BS. :)
    Hope all is well Wire.

  4. Edward Teach says:

    Meh. I have .410 written in crayon on the barrel of my Guide Gun.

  5. Firehand says:

    Ran across something on the problems/non-problems at different times with 5.56 stopping bad guys:

    This is downright weird.

  6. AM says:

    Guy doesn’t understand that pressure is the same, but measured differently. Guy doesn’t mention milspec port pressure requirements. Guy repeats the lie that milspec brass is thicker than civilian 223 brass.

    This guy is not a good source.

    • Wirecutter says:

      I pulled the bullets, cut the brass midway from the base and mic’ed the brass from both a new 5.56 and 223 round once. The milspec brass was .001″ thicker. Yes, it was and that relates directly to pressure. Not enough to make a catastrophic difference, but it was thicker.
      Granted, I only did 2 rounds but still…..

  7. James says:

    I find what works and try and stick with it. All I want is reliable good feeding/ejecting ammo. This is relatively easy for mil spec weapons. Or it was. Much of what I used to buy is no longer or seldom available.

    On the civilian side I once got told at the counter of a gun store that I was buying the wrong rounds for one of my rifles. I was surprised as I took it from the right area. Well, no, he was right. It was not what was listed. Read the box always… Good catch from my friend/owner of the store.

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