Caliber: .223/5.56 X 45mm NATO

LearningLearning MemberPosts: 46 Member
Hate to ask, but I need the help.

Can someone please explain what each of these dimensions mean?

Caliber: .223/5.56 X 45 mm NATO

Comments

  • JermanatorJermanator Senior Member Posts: 13,747 Senior Member
    The .223 is inches. 5.56 is millimeters. That is the diameter of the bullet for that cartridge. The 45 millimeters is the length of the cartridge case.
  • LearningLearning Member Posts: 46 Member
    Jermanator wrote: »
    The .223 is inches. 5.56 is millimeters. That is the diameter of the bullet for that cartridge. The 45 millimeters is the length of the cartridge case.

    So the .223 and 5.56 is the same, just different unit of measure. This is the actual bullet?

    And the 45 is the case the powder is held?
  • JermanatorJermanator Senior Member Posts: 13,747 Senior Member
    Yes, and yes. When it is called .223, they are referring to the .223 Remington cartridge. This is a civilian/commercial version of the military 5.56 NATO (5.56x45). The two cartridges are almost identical, but there is a bit of pressure and dimensional difference.
  • JayhawkerJayhawker Moderator Posts: 13,524 Senior Member
    Very basic simple answer.....223 Remington (Civilian) and 5.56 X 45 NATO (Military) are pretty much the same cartridge...pretty much...there are some differences that may or may not be important dependin on how your rifle is chambered.
    It's one of the many "hot rod" .22s....
    Sharps Model 1874 - "The rifle that made the west safe for Winchester"
  • snake284snake284 Senior Member Posts: 20,678 Senior Member
    Well sort of. They have basically the same measurements, with the exception of the neck of the chamber, but not every firearm marked as .223 Remington is safe with 5.56x45 Nato because the Nato round is rated at a higher pressure. Just make sure your firearm is rated to shoot 5.56x45 NATO. Some .223s are rated to, and some are not. Either look at the paper work that came with the firearm, or call the manufacturer and ask. If you don't know, then assume the firearm is a .223 Remington only and don't fire the Nato rounds through it.
    Daddy, what's an enabler?
    Son that's somebody with nothing to do with his time but keep me in trouble with mom.
  • jbohiojbohio Senior Member Posts: 5,338 Senior Member
    With AR type rifles, it's OK to shoot .223 Rem in a 5.56 marked barrel, but not necessarily the other way around.
    Most manufacturers these days are chambering .223 AR's with a .223 Wylde type chamber which is OK for either round.

    The big difference is the throat, or leade of the chamber. 5.56 brass is just a tad longer than .223. If your rifle has a standard .223 chamber, there is the possibility that 5.56 brass could be too long for the chamber, and the brass sticking in to the bore, causing a pinch point, and dangerous over-pressure.
    Also, the 5.56 is rated for higher pressures.

    Like I said, most .223 AR's have a wylde type chamber these days. It'll be in the paperwork, or a quick call to the mfg. will sort it out.
    Generally speaking, never put 5.56 rounds in a .223 bolt action.
    http://en.wikipedia.org/wiki/.223_Remington

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