.223 crimp vs no crimp

Discussion in 'The Ammo & Reloading Forum' started by lslubecki, May 4, 2006.

  1. lslubecki

    lslubecki New Member

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    I have been reloading .223 and not crimping the case when done. The rounds seem to shoot very well. Should I be crimping or not. The bullets are tight in the case. I am using different brass, 55gr fmjbt with 24.5 gr 's of IMR4895. Thanks for your expertise.

    Steve Lubecki
  2. SDLAW

    SDLAW New Member

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    If you are shooting a bolt gun you do not need to crimp and in fact it may result in reduced accuracy if you do. Auto guns may need to be crimped to prevent the bullet from being pushed back during the cycling of the gun during firing.
  3. inplanotx

    inplanotx New Member

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    Can you please tell me how you would get reduced accuracy with a crimp? In all my years I have found just the opposite. You get better accuracy with a crimp due to the powder burning more thoroughly with to the crimp holding the bullet just a little more before launch. The way to see it is with a chronograph and the SD of a shot string comparing crimped vs. no crimp.
  4. LDBennett

    LDBennett Well-Known Member

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    inplanotx:

    I think those that cringe at the thought of a crimp do so thinking that the operation of crimping will deform (somehow?) the case so that all the efforts to keep the case and bullet parallel axially and the relationship of the bullet to the bore in line, will be destroyed. That is probably a fallacy.

    But if a crimp is what you need the Lee "Factory Crimp" die is the best I have seen. And Lee claims (and claims to have proof) that the accuracy indeed gets better with the use of their die.

    Personally I do not crimp ammo for bolt guns and only crimp ammo for semi autos. Perhaps I believe the fallacy too (???). But I find that the crimp feature of regular dies requires fiddling with the set up of the dies and exacty correct brass overall length. I usually have those conditions but not always so I avoid the crimp step except with the Lee Factory Crimp seperate die.

    LDBennett
  5. lslubecki

    lslubecki New Member

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    I am shooting an AR-15. I do have the Lee crimp die and I did crimp a few and not the rest and have not had a problem with bullets pushing back into the brass. I was concerned about the pressure issue but my shoulder feels no difference and my target pattern is not any better or worse with or without the crimp.

    Steve Lubecki
  6. SDLAW

    SDLAW New Member

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    I am not saying that an accurate load cannot be achieved when crimping is used, but any change in the loading process can and usually does affect accuracy.The premise was that he had already developed an accurate load without crimping. Crimping can have a dramatic influence of the the pressure curve which can dramatically change how that particular load works for that particular bullet in that particular gun. How the crimping is performed can also make a significant difference since it may be influenced by a number of factors such as bullet type, case length and the brass used.
  7. lslubecki

    lslubecki New Member

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    I will check the length of a few rounds in the clip as I shoot to see if the length changes. All the rounds had fired so I assumed no length changed. My main concern was for safety of myself and the gun and any others that may be nearby shooting. I had ejected a few rounds when cease fire was called and the bullets looked ok but I didnt actually measure any. I will bring mics with me next time out and measure and I will repost. Thanks for the info.

    Steve Lubecki
  8. Crpdeth

    Crpdeth Active Member

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    Steve, crimp those babies for use in an AR-15! If and when a problem arises it may very well be more than a felt recoil problem!

    Crpdeth
  9. stash247

    stash247 New Member

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    Crimping affects accuracy in relation to the variation of case length and neck thickness--- Shooting 'mixed lot brass' , as most of us do, in AR's, Mini 14's, and such, a difference of .001" in case length makes for considerable difference in 'bullet pull', and consequently, in pressure. Neck thickness variation only compounds the problem.
    Benchrest shooters use, often, a single case, marked for '12 O'clock' chamber position, to minimise these effects, and maximise accuracy.
    Flip side, for a self loader, is that without a crimp, one runs the risk of driving the bullet back into the case, on the loading cycle, with the potential for gun-wrecking pressures.
    Pick your poison!
  10. lslubecki

    lslubecki New Member

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    You have all convinced me to crimp. I have the die but was lazy in the reloading process. I felt that the bullet was firm enough in the case but I sure dont want a case rupture. Close groups would be nice too but as long as I can get 4-5 inch groups at 100 yards I'll be happy (no scope, iron sights for me). And with practice I am sure the groups will tighten up. Thanks for the great info.

    Steve Lubecki
  11. BigSlick

    BigSlick New Member

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    I've loaded and shot a lot of .223 over the years, both semi and bolt guns.

    I don't crimp for bolt guns at all, with semi only for long(er) range work.

    A variance in SD won't affect accuracy in short range shooting enough to accurately, repeatably measure. SD variance will make a significant difference in shots over 4-500 yds as velocity deviation will adversely affect bullet impact.

    For blasting or plinking ammo for the AR as long as you have *good* neck tension, a crimp shouldn't be needed to prevent setback.

    If you want to take the time to measure neck diameter of sized brass, you can get a good idea if a crimp might be something you should implement. I have found most factory die dimensions will give adequate neck tension, provided your brass isn't severely over worked or out of spec.

    HTH,

    BigSlick
  12. frhunter13

    frhunter13 New Member

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    The AR has the lowest recoil of any high power rifle I have ever fired. I can see the requirement for a crimp where the recoil is from a Mini 14 or other rifle that actually kicks.

    If they need crimping its because of the slam into the chamber or knockabout in the mag while in combat.

    Id like to see some evidence there could be a problem before I worry about crimping my range ammo.

    In either case, try finding a 223 crimp die anywhere now. The shelves are dry thanks to .... Well we all know who.
  13. frhunter13

    frhunter13 New Member

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    Consistency is the game for target shooting, once the sweet spots are found - including distance from the bullet to the lands. Crimps are not consistent. They just aren't.
  14. steve4102

    steve4102 Former Guest

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    Lee Factory Crimp vs No Crimp.
    Colt AR-15 5.56, 16 inch barrel.
    55gr Varmint Nightmare HP.
    10 rounds each target
    100 yards

    [​IMG]
  15. whiskeypickles

    whiskeypickles New Member

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    On my AR's I don't crimp, due to the fact my chamber is 5.56 and I also shoot 223 in it. What I did was to turn my Lee expander plug down .002 and just seat the bullet. with the recoil from an AR no problem with set back and they shoot very accurate.
    55gr FMJBT
    Wolf 223 primer
    25.5gr TAC
    1" or better @100yrds if I do my part
    Last edited: Feb 10, 2013
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