Crimp when collet sizing?

Discussion in 'The Ammo & Reloading Forum' started by azleite, Oct 4, 2009.

  1. azleite

    azleite Member

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    Hi Folks, I'm sure this has been asked before but,here goes:I've been collet sizing 100 pieces of .223 Rem. brass for my Howa 1500 varmint. All I do with this rifle is target shoot at 100 yds.On the instruction paper that comes w/this Lee die it mentions it's crimp die.Would crimping improve accuracy or is it even needed? I do have a crimp die with the rest of the set as I also load for my AR.Thanks for any advice-Dave
  2. JLA

    JLA Well-Known Member

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    For the AR crimping is a must. For your bolt gun its really not needed, especially on target ammo. Seat your bullets .005 to .015 off the lands and shoot away. Crimping does affect pressures and powder burn by adding bullet pull. But is mainly recommended for autoloaders like the AR because bullets can get crammed back into the case if the bullet jams against the feed ramp during feeding. Its one of those do it if you think it helps sorta things when loading for a bolt gun but is a do it no matter what sorta thing for an autoloader... Make sense?
  3. azleite

    azleite Member

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    Thank you for the help JLA-Dave
  4. KellyTTE

    KellyTTE New Member

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    :rolleyes:

    To quote a former US Army AMU commander:

    In other words, crimping is for very specific situations and generally NOT needed if the rest of what you're doing is correct. It doesn't matter if its a bolt or an auto gun. Folks need to quit spreading mis-information.
  5. LDBennett

    LDBennett Well-Known Member

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    KellyTTE:

    While you may follow anyones suggestions you like, I am of the opinion that no one knows more about reloading than the reloading book publishers and manufacturers of reloading components and supplies. I follow their suggestions of crimping ammo that is to be used in semi-auto guns. They also recommend crimping lever and pump gun ammo for those guns that store ammo in a tube, end to end. Also note that every round you buy commercially is crimped, regardless of its usage.

    The way to reproduce the factory crimp and not distort the bullet is to use the Lee Factory Crimp Die which uses a collet to make the crimp.

    People often come up with "different" approaches to reloading that don't follow the rules set out in reloading manuals. Sometimes they get better results and sometimes they create unsafe conditions. I think it better to follow the reloading manual rules. There has been more than one gun out there damaged by following "expert" advice. I also think that this particular information on crimping semi-auto, and tube fed lever and pump guns ammo NOT to be mis-information. But you, of course, can do it however you like. I just want others to know that your way is not the recommended way.

    LDBennett
  6. Bindernut

    Bindernut Well-Known Member

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    And to add a little more info (or confusion) to the crimp or not crimp debate...

    If a bullet doesn't have a cannelure, then don't crimp it other than maybe lightly forming the case mouth back against the bullet. Don't force a crimp on a bullet that doesn't have that crimp groove...that WILL introduce those jacket/core irregularities that are mentioned in the quote that KellyTTE has posted.

    I don't own any semi-auto rifles at the moment, but in the past I have had problems with bullet creep (setback) so on those rifles I use a bullet with a cannelure and a crimp. Same goes for tube-mag guns or any hard-kicking lightweight (even if it's a bolt).

    A bolt-action, varmint-weight .223 I wouldn't think that a person would need to use a crimp...not much recoil in that situation.
    Now, for instance, a Model Seven in .358 Winchester...the one I own does need a crimp because one shot will cause creep in the rounds in the magazine.
    Each rifle/ammo situation should be evaluated for what needs to be done. Just like finding a pet load...What works for one rifle doesn't work for all.
    Last edited: Oct 5, 2009
  7. JLA

    JLA Well-Known Member

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    Indeed:rolleyes:;)
  8. JLA

    JLA Well-Known Member

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    Magnum handgun cartridges will not perform consistently without a heavy crimp and the bullets will walk out of the case under recoil when fired from a revolver thus locking the revolver up, and it only happens when you do not apply a heavy crimp to the cartridge... I have also had ARs jam with certain bullets, hard enough to distort the nose under spring pressure, Im 99% sure that without a firm crimp from a Lee Factory Crimp die they would have been pushed back into the case creating a high pressure round if it were to be fired. I have had bolt guns shoot quite well without a crimp and some shoot better with a crimp. Bolt guns are less finicky about bullet crimp because they arent being fed by lightning fast recoil forces and heavy spring pressure and most of the time are being fed into the firearm one at a time from the bench... All hunting ammo should be crimped just for safetys sake. If you use a LFCD properly it wont effect a bullets core and jacket anymore than the rifling cutting into the bullet will and we all know that has to happen before the bullet exits the barrel and hits the target. My go to AR .223 loads with sierra 53 gr matchkings loaded over 25.5 gr IMR 4895 with a fairly heavy factory crimp shoot 3/4 MOA from a 16" heavy BBL. If you were to pull the bullets (they dont have a cannelure) they have a fairly deep ring where the crimp was set. I do not quote people that 'I think', know what they are doing. All of my advice is given from experience and based around what I find works best for me. As a gunsmith I cannot always rely on what others claim is fact, in most cases I have to find out fact for myself. I trust you will find this information helpful and answers your initial question Dave, BTW, welcome to the forum;)
  9. LDBennett

    LDBennett Well-Known Member

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    I shoot my AR-15 clone varmint gun with Hornady 75 gr HPBT Match bullets using the Lee Factory Crimp Die setup for a light to medium crimp. The gun averages 5/8 inch five shot groups over five groups at 100 yds. I really don't think the LFCD affected the accuracy of this gun and this load!

    LDBennett
  10. GMFWoodchuck

    GMFWoodchuck New Member

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    What he said.....
  11. steve4102

    steve4102 Former Guest

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    Many of the crimping naysayers have never even seen a LFCD let alone tried one. The LFCD does exactly what is claims to do. It holds the bullet more secure, something that is a must in an auto-loader and INCREASES accuracy. So what's not to like? Increased Accuracy, additional safety and Reduced SD.
    I know, I know Speer and others claim the LFCD will degrade accuracy a much as 40%. This is nothing more than a childish pissing match between Richard Lee and Speer. I have never had a properly applied Lee Factory Crimp degrade accuracy, never.

    Here is a link to an accuracy test using the LFCD. Note the comments at the bottom of the page. Also note that NONE of the bullets tested had cannelures.



    http://www.accuratereloading.com/crimping.html


    As for the need to crimp in an auto-loader, read this. It is from Sierra's Exterior Ballistics web page.

    Neck Tension

    When we stop to consider the vigorous (read, downright violent) cambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

    There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition
    To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension.
  12. steve4102

    steve4102 Former Guest

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    This just caught my eye. Are you sizing your AR brass with the Lee Collet Neck die also?? If so, not such a good idea, AR and other semi-autos should be FL sized.
  13. Popgunner

    Popgunner New Member

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    I'm enjoying this thread & have learned some new things.

    It reminds me of a hunt 6 of us took in Wyominjg a few years ago. My buddy had tweaked all the accuracy he could get out of his 7mm mag bolt rifle. He had decided not to crimp & to seat the bullets just off the lands. He had showed me how from the bench it would shoot 1-1/4" groups. We were jumping back in my truck on the hunt & when he pulled the bolt back to unload the bullet stayed firmly in the lands. Having no rod with us he shot with my gun that trip. Very disapointing for him. I would add that I crimp all hunting loads to the list.
  14. KellyTTE

    KellyTTE New Member

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    Although manuals and factory guides are valuable sources of information, the shooting world obviously goes far beyond the starting point where manuals leave off. Is there a time and a place for crimping? Sure, I taper crimp all of my pistol ammunition and I've tried just about all the major crimp dies out there for rifle, including the stock Dillon, Lee FCD, etc.

    Factory manuals balance between several compromises including performance, ability, skill, attention to detail and of course, the ever present lowest common denominator reloader.

    But when I have a SME on the AR platform, who has round counts in the millions, that has a staff of which every single member has a 'Presidents 100 tab' on their shoulder says 'this is how I do it for competition and killing stinky badguys' I sit up and take notice. When advice like this comes from someone like the LTC, I think its what the the police call a 'clue'.

    For the record, in the last 6 months I've loaded and shot over 4,000rds of .223 using this manner with exactly one failure (dud primer) in both 16" and 12.5" ARs. This is not slow bench fire, this is all competition and high round count training. So I know that it works, for me.
    Last edited: Oct 5, 2009
  15. azleite

    azleite Member

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    Hi again Folks, Sorry if I caused any confusion, when I originally asked about the crimp I was refering to ammo loaded for my bolt action .223. I always full length size & crimp for my AR loads. I keep the 100 pieces of brass seperate for my Howa as they are fire formed for it's chamber. I'm still new at reloading so I do appreciate all input,Thanks again folks-Dave
  16. KellyTTE

    KellyTTE New Member

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    Sorry for hijacking your thread. :(

    I was simply responding to the 'all ar ammo needs to be crimped' comment.
  17. azleite

    azleite Member

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    No need to be sorry Kelly, like I said, I'm grateful for all input-Thanks again-Dave
  18. Gearheadpyro

    Gearheadpyro New Member

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    I load for a .308 Remington 700 that has been well modified. It has not had the barrel replaced or the action trued. I just recently acquired a Lee Factory Crimp Die and have been experimenting with its use and / or benefits. I am sizing the 3X fired brass with a Lee collet neck sizing die.

    First, Crimped ammo seems to have slightly higher velocities then non crimped ammo with the same powder charge as all of my crimped rounds shot high. I do not have a chronograph so I cannot measure the differences.

    Second, Crimped ammo has a SMALLER average group size. This has proven so with 165 gr Hornady SST's and 175 gr Sierra Matchkings. The Hornady SST's average .5"-.6" depending on me uncrimped, crimping is getting .4" - .5". Group size is also much more consistent with the crimp as opposed to getting some .3" groups and some .9" groups. The Matchkings I am still working on my load for, but the uncrimped loads also tend to average .1" larger groups. All shooting is done prone from a bipod with a bean bag in the rear.

    Third, Crimping into the cannelure of the SST's opened group size up a bit. My gun seems to like the SST's at 2.810" COAL with or without the crimp. This is still a good ways off of the lands thanks to Remington's lawyer designed chamber. The Matchkings do not have a cannelure so I cannot make a comparison there, my COAL with them is 2.900". Once again this is still well off of the lands.

    I'm going to keep experimenting with the Crimp Die, but as of yet I think I like it. It seems to have improved consistency of the ammo, and has shrunk group size. They are inexpensive enough that I think it is certainly worth the buy to experiment with.
  19. JLA

    JLA Well-Known Member

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    Striking similar results for me as well Gearhead. I love the LFCD. BTW, welcome to the forum;)
  20. Archie

    Archie Member

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    Ammunition is crimped for a couple reasons.

    One is to prevent bullet movement in the case. As mentioned, revolvers with heavy recoil will actually 'pull' bullets out of the case just like an inertial bullet puller. I've had it happen with standard level .38 Special rounds in a S&W Chief Special revolver. (Not with wadcutter loads, however.) Also, a magazine type pistol or rifle will tend to push rounds deeper into the case if recoil is significant. Especially lever guns.

    The other reason is to assist in initial ignition. One wants the powder charge to get fully involved early on in the combustion process in order to insure full and consistent ignition.

    All that said, a very tight neck fit in a bottle neck cartridge can be sufficient for both purposes. One cannot argue with results.

    Therefore, I suggest you experiment with the process and find out which method works best in your rifle. If you get good results and someone tells you what you is wrong, smile sweetly and tell them you'll take it under consideration. Then keep doing what works for you.

    For the record, I crimp most everything - except for some rifle rounds wherein I seat bullets to the leade and bypass using the magazine.
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