Switching front reloading 223 Remington to 5.56 NATO.
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Thread: Switching front reloading 223 Remington to 5.56 NATO.



  1. #1
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    Switching front reloading 223 Remington to 5.56 NATO.

    I want to get a Long Ranger 5.56 NATO. I already reload for 223 Remington.
    How does reloading for 5.56 NATO differ from reloading for the 2.23 Remington ?
    How does the extended throat of the 5.56 NATO affect reloading?
    Does OAL differ?
    Is there different data available? All I find is 223 data.
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    Tim​
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    Nosler's reloading manual (avail hard copy or online) has both a 223 section and a 5.56 section:

    https://load-data.nosler.com/load-data/556x45-nato/

    https://load-data.nosler.com/load-data/223-remington/

    Regards, Guy

  3. #3
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    Quote Originally Posted by M700 View Post
    Nosler's reloading manual (avail hard copy or online) has both a 223 section and a 5.56 section:

    Regards, Guy
    ok I see that now. I'm also seeing how it is implied in the data from others.
    Thanks
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    Tim​
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    Gun Wizard
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    See that is basically a copy of the BLR. You basic question, requires alot of answers. Several of the powder manufactures list 5.56 loads seperate from 223, within their on line manuals. With the common 55gr and 62gr bullets the COL remains the same, this is because the bullet canlures for crimping is the determineing factor. What they up is the powder charge for the 5.56. With the huge variety of mostly heavier bullets without a canlure the additional length of the 5.56 chamber can be utilized. This COL going to vary by bullet. An RCBS Case Mic set would be very helpful in setting up an accurate load, from figuring the max COL for each specifc bullet, and allow for resizing right at or just below minimums which often enhances accuracy and extends case life. As you run a reloading sessions for time to time, you can use the case mic to insure each batch is to the exact same standard of the last as far as resizing in relationship to headspace, and producing the exact same COL. This same case mic alows you to accurately adjust headspace (resizing) and COL up and down by something as fine as like .001 inch when searching for that most accurate reload.
    Last edited by graymustang; 11-22-2018 at 06:00 PM.
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    Sidewinder
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    There are very tiny differences in the SAMMI specs for the cases. The main difference is the pressure they get loaded to.
    The 5.56 gets loaded to higher pressure than the 223. The 5.56 has a longer throat to help with shooting longer bullets as well has helping keep pressures within spec. It need this higher pressure to function the action of semiautomatic rifles.
    Some manufactures claim the 223 rifles can't hold up to 5.56 pressures. Other just use a 5.56 chamber.
    If your loading your own, you can load up to the pressure your gun is capable of. This means very careful load development. Measuring case heads with a micrometer as well as watching primers is the recommended methods. Case life from expanded primer ;pocket as well as cases separation indicate extreme pressures. If you get this after one or two loadings your too high.
    You may find your rifle likes loads a bit hot, maybe it won't. I try not to push too hard. I load for accuracy not velocity. An exra 100 fps isn't worth it if it opens a group.
    Leo

  7. #6
    Sidewinder
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    I did a bit of research. The 223 chamber has a throat of .224 did meter and isn't very long. The 5.56 has a .225 or so throat that is much longer.
    This larger, longer helps the rifle handle the higher pressure, 62000 psi vs 50,000 psi.
    My 223 may have a 5.56 chamber. It may have what they call a Wylde chamber. This chamber has the same .224 diameter throat but it is as long as a 5.56 throat.
    The Wylde chamber can handle the 5.56 pressure. Being cut to tighter dimensions it is claimed to be more accurate than the 5.56 chamber.
    In my 223 I have shot both 223 and 5.56 ammo with no issues and good accuracy. That's with factory loads.
    I didn't have a chronograph at the time. Perhaps I ought to get it out and shoot some of both to compare velocity.
    I would expect the 5.56 will be faster.
    Leo.
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    The current 5.56mm NATO cartridge case is somewhat thicker thicker in the web section. This results in less case capacity. The reloader needs to take this into account when loading NATO marked cases.

    Current NATO chambers feature a secondary angle at the base of the case neck at the shoulder. It kind of blends the angle. FN touts this feature as reducing the occasion spike in pressure. The back story is that this feature is the result of the forging process which can not duplicate the SAAMI spec shoulder squeezing the metal into a near sharp SAAMI spec angle. The improvement was entirely an accidental improvement finding during pressure tests.

    Some chamber reamer manufacturers offer this improvenet in their conventional reamer product line. A forging company I am acquainted with discovered this 'feature' trying to forge chambers in 5.56mm NATO. The forging process simply can not 'pack' cold forging alloy steel into a sharp corner.

    Not to be concerned about, a properly forged barrel will out last a cut rifled barrel in round count. Cut barrels still seem to lead in the accuracy department.

    AC

    I looked on line and now find no references on GOOGLE nor DuckDuckGo. I find this a bit intriguing.

  9. #8
    Marlin Marksman
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    The differences are accounted for in the OAL and powder charge both as defined in your reloading data. Only thing to note is if you use 556 brass for either 556 or 223 you have to account for the reduced case capacity as 556 brass typically has less internal capacity.
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  10. #9
    Gun Wizard
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    The 5.56 throat is longer, because some of the earlier tracer bullets were longer. As mentioned this creates freebore for a 223 or 5.56 not firing this particular bullet or one very similar. It is not a good idea to fire hotter 5.56 loads in a 223 chamber, but the reverse is okay.
    "Should have put more dirt down, saw it right off." Bear Claw in Jeremiah Johnson



  11. #10
    Deadeye
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    The 5.56 gets loaded to higher pressure than the 223.
    Actually, not so much. The NATO spec is CIP, measured a a different point
    https://ultimatereloader.com/2018/08...cts-and-myths/https://ultimatereloader.com/2018/08...cts-and-myths/

    The 5.56 has a longer throat
    True. It is more forgiving against getting jammed into the lands with certain bullet shapes.


    As to "loading differently" between the two.... don't lose any sleep/overthink it too much.
    If the NATO section shows a different OAL for a specific brand bullet, use that OAL.
    Last edited by mehavey; 11-28-2019 at 08:09 PM.
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