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Must I crimp my .223 for AR?

Discussion in 'Handloading and Reloading' started by H1500308, Mar 21, 2008.

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  1. H1500308

    H1500308 Member

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    I've loaded around 100 rounds of plinking ammo for my Armalite. Must I crimp the rounds? The bullet seems very tight after running through the seating die.

    I guess my question is when to and when not to crimp??
     
    Last edited: Mar 21, 2008
  2. 308win

    308win Member

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    I don't crimp for my AR (also an Armalite). AR's don't recoil hard enough for bullet movement to be a concern. YMMV
     
  3. taliv

    taliv Moderator

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    it's not normally a requirement, but it's a good idea. I crimp all my non-match ammo.
     
  4. fourrobert13

    fourrobert13 Member

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    I don't crimp and I haven't had any problems with any of my AR's.
     
  5. Floppy_D

    Floppy_D Member In Memoriam

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    I made 100 rds of 55g HPBT, and crimped half. I made 5 10 shot groups of each, and compared the results. There was not significant enough evidence to make we go one way or another. Therefore, I crimp simply because it's sturdier. I have no evidence of a bullet shifting in the brass in an AR, but this way I don't have to look for it.
     
  6. Historian

    Historian Member

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    I give each of my rounds a slight taper crimp.

    Historian
     
  7. mallc

    mallc Member

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    To crimp or not to crimp?

    Oniy crimp if the bullets have a canulla (sp?) that little serrated ring. Seems that high end dies don't recommend crimping at all.

    I've also reduced the crimp on my pistol dies and have improved accuracy.

    Scott
     
  8. Slamfire

    Slamfire Member

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    Don’t crimp. If your bullets are nice and tight in the case neck, they are not going to move.

    I do not believe in crimping rifle ammunition. No Nationally ranked Highpower competitor crimps their match ammo. That tells me that crimping does not increase accuracy. At best, deforming your bullet through crimping does nothing.

    This is advertising induced behavior.
     
  9. Roccobro

    Roccobro Member

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    Does the US military crimp their rifle rounds? Not all reloading is for just accuracy so this question comes up almost daily here..

    If there was no bullet deformation, and POI doesn't change, is there a reason NOT to slightly crimp?

    Justin
     
  10. taliv

    taliv Moderator

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    are Highpower competitors ranked nationally? got a link to this ranking?
     
  11. Ridgerunner665

    Ridgerunner665 Member

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    Crimping can and does decrease accuracy...because it damages the copper jacket of the bullet.

    If the bullets have a cannelure... I crimp them because the bullets can get "setback" from feeding...just like a 1911 pistol.

    The Hornady 60 grain V-MAX bullets I been using on coyotes don't have a cannelure....and crimping makes the groups a whole 1 inch bigger at 100 yards....so I don't crimp them...I fill the case up with 26 grains of Reloder 15 powder (its a safe load in 5.56x45 chamber...DO NOT USE in a 223 Remington chamber) which is a compressed load...that keeps the bullets from pushing back in the case during feeding.
     
  12. Slamfire

    Slamfire Member

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    If crimping does nothing, then what is the purpose?

    My experience is that it swages the mid section of the bullet. My bullets came out deformed. When I am spending 25 cents or more for a bullet, what can I do with some hand tool that will make that bullet shoot straighter than what the manufacturer does, with millions of dollars of equipment?


    Not really. For a time the NRA was putting out a list of top 200 shooters in the Nation. Since I don't subscribe to the competition magazine they put out, I don't know if that list is still published.

    However, if you shoot at the Nationals, you get squadded with the best shooters in the world. The talent is awsome, and they are on your left, right, or with you on your firing point. You recognize names, because they are winners that you remember, guys or ladies who are consistantly in the top 10 or 20, and you get to ask them questions.

    They don't crimp. Neither does the AMU or the USMC rifle teams.
     
  13. Roccobro

    Roccobro Member

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    Who said it does nothing?

    Military crimps their primers for a reason, I figure they'd crimp the bullet for a reason also. That is why I posed my question. If crimping the bullet in your experience swages the bullet, that is some serious crimp and beyond what I'd consider "slight". I'm thinking light enough like you'd do for a plated bullet without cutting into the plating.

    Justin
     
  14. taliv

    taliv Moderator

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    edit: i doubt it's for the same reason. i imagine bullets are crimped to prevent setback and primers are crimped to reduce the odds of them winding up wedged between the lower receiver and trigger.
     
  15. Ridgerunner665

    Ridgerunner665 Member

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    Taliv nailed that one.
     
  16. Slamfire

    Slamfire Member

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    I followed the direction on my Lee Crimping tool. I was crimping 168 SMK into 308 match ammo. I crimped a few and disassembled the rounds only to find the bullets were heavily swaged. So I tried "light" crimping were you could not see any crimp tool marks on the case neck. The bullets were only slightly less deformed.

    Shot all the bullets at 100 yard matches or when chronographing loads for velocity. Surprizing thing was, they actually shot well. But then, I was only getting started too.

    Perhaps I anticipated too much into the question. Taliv has it right. And the military does some other things we don't do. The US military used to put tar on the bullets. I have never tried to disassemble any LC .223, but the good old 30-06 and 308, those bullets were coated with tar. For the same reasons as stated by Taliv.

    I don't know anyone who dipps their bullets into hot tar before seating. But I will bet the day a major manufacturer sells a hot tar tool, there will be people claiming what a good thing it is.
     
  17. taliv

    taliv Moderator

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    for the record, i don't think deforming the bullet is the source of theoretical inaccuracy associated with crimping.

    i'm way outside my lane here, but i can't help but notice the barrel itself is quite a bit smaller than the bullet. examining the gully left by the lands on recovered bullets makes me think the process of squishing the bullet through the barrel does way way more to deform a bullet than crimping possibly could, and yet, accuracy is fine.

    the problem with crimping relative to not crimping is simply uniformity of neck tension.

    if all you're doing is making sure your necks are round and a consistent ID/OD, and I have to do that plus squeeze the brass into the bullet, seems like you've got an advantage.
     
  18. Roccobro

    Roccobro Member

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    Me too. ;)

    So if people want their ammo to work the same as the military did (to go bang and send a projectile -without failure) should they re-manufacture their ammo with similar practices? (exclude WWII tar on 30-06 example of course, just talking crimp here)

    ORIGINAL POSTERS QUESTION:
     
  19. Ridgerunner665

    Ridgerunner665 Member

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    Taliv,
    Damaging the jacket does affect accuracy...it affects the alignment of the bullet in the bore, and it also has an impact on the pressure...it creates varying resistance, depending on how much damage was done to the jacket (<<< no 2 are damaged exactly the same amount or in the same way)...which in turn makes the velocity vary.
     
  20. 3rdpig

    3rdpig Member

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    I only use bullets with cannelures when I load for an AR and I crimp them using a Lee FCD. With a mixed bag of cases, powder dropped from a powder measure and coming off a progressive press, my blasting ammo gives me 2" groups at 100 yards. This meets my needs for this type of ammo. If I separate my cases, weigh each charge I can halve those group sizes while still crimping.

    If I was shooting competition I might want better than MOA accuracy, but I doubt I'd be using off the shelf AR's and AR barrels with stock triggers at that point.

    Crimping for the AR isn't to prevent the bullet from moving under recoil, it's to prevent bullet setback when the bolt forces it up the loading ramp. There just is'nt a lot of neck tension with most of the 223 cases I've loaded. Having a boat tail bullet helps force a bullet into a slightly undersized case mouth, but even then I find that the bullet isn't held that tightly.

    When loading 223 for a bolt action or single shot rifle, I never use bullets with cannelures and never crimp.
     
  21. Southern Raider

    Southern Raider Member

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    Highly regarded competitive shooters may not crimp their ammo using the classical methods we are talking about it here, however, I am reasonably sure they do other things to assure consistent neck tension.

    For example, look how a neck bushing die works during the sizing process. This tightly controls the neck dimension, and the size is selected from the bullet used. In other words, the size of the neck die, plus the elastic nature of the brass is used to effectively grip the bullet and is done at the sizing stage. They get want they want (a crimping type operation) but it is done in a manner where the bullet is not subjected to the operation.
     
  22. 30Cal

    30Cal Member

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    60lb neck tension requirement. I have no idea what the rational is behind the requirement, but I suspect, as all things .mil are, that it's overkill.
     
  23. Slamfire

    Slamfire Member

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    You would be surprised in the extreme spread of reloading technics. The gunsmith who does my M1a and Garand work, he is a Distinguished HM. He has got every medal you can get. He would use the same set of brass for a season, never removed the RCBS case lube, only trimned when he noticed that the case was hard on the upstroke in the sizing die. He would take the case out and shorten it with a hand file, and toss it with the rest!

    There are a surprising number of shooters who are absolutely outstanding shots, and are very casual in their reloading technics.

    There are others who do every case prep technic you ever heard of. There are less of these as you have to have a lot of ammo if you shoot a lot.

    But most would tell you, it is more important to concentrate on your sight alignment and trigger pull than anything else.
     
  24. rbernie
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    rbernie Member

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    Crimping is usually done either to keep bullets from pulling under recoil or setting back under the forces of feeding. It is not done to increase accuracy. In my informal 100yd testing, the presence/absence of crimping has a minimal effect upon my group sizes. Longer ranges or better shots may be able to tell a difference.

    The AR15 may not generate recoil sufficient to pull a bullet, but the feed cycle is pretty brutal and the feed path (thru the locking lugs) pretty torturous. I have seen bullet set-back with 223 handloads that had good neck tension and did not utilize a finishing crimp; they were my first AR reloads.

    As a general rule, when reloading for a semiauto it is considered a good idea to use bullets with a cannelure and crimp the case neck into the cannelure. For my ARs, I sometimes use bullets without a cannelure but I always use a Lee FCD regardless of the presence/absence of a cannelure.
     
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