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crimp?

Discussion in 'Ammunition & Reloading' started by trainwreck, Apr 4, 2011.

  1. trainwreck

    trainwreck salem Member

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    how do i know if i am crimping to much or not enough?

    im loading 45acp with 230gr berry plated RN bullets.
     
  2. Blitzkrieg

    Blitzkrieg WA Well-Known Member

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    I use a taper crimp on auto pistol rounds.. improves feeding and safety. You just gradually increase the taper until the case is slightly set into the bullet but you can still barely feel the case edge
     
  3. Shooter98

    Shooter98 McMinnville, Or. Member

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    I do the same as Blitz. I only crimp auto loaders and I use Lee collet taper crimp dies. I also will crimp for my bolt rifles if I am going to be doing any drills with them and they might get shook up some.
     
  4. jib

    jib Central OR Active Member

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    "how do i know if i am crimping to much or not enough?"

    In a auto loader I use the crimp die to remove the case flare. The minimum OD of the case mouth should not be less than .469", the cartridge head spaces off the case mouth so over crimping should be avoided.
     
  5. trainwreck

    trainwreck salem Member

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    thanks for the info. looks like i need to crimp just a bit more.
     
  6. Shooter98

    Shooter98 McMinnville, Or. Member

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    Sorry, I guess I avoided the obvious question you had. My answer to how to know if you have crimped too much is you'll see it. When you start marring the brass and/or crushing the bullet it's too much lol...
    I crimp very lightly, not enough to show on the brass but enough to where I cannot get the bullet to move at all with my fingers.
     
  7. jib

    jib Central OR Active Member

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    "not enough to show on the brass but enough to where I cannot get the bullet to move at all with my fingers."

    If the the expander/flare die is the proper diameter the bullet will have adequate case neck tension without a crimp and should not move. A minimal crimp is extra insurance to prevent bullet set back, as long as the outside case diameter at the case mouth is not less than .469"the round will head space properly. Assuming the COL is correct.
     
  8. jer fly

    jer fly cottage grove Member

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    using your dial calipers measure the case mouth. The correct crimp ( taper only ) should result in a measurement of .470 on cases that measure .8880 min .8980 max in length.
     
  9. NWnewguy

    NWnewguy Poulsbo New Member

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    I just use the Lee factory crimp die. It makes it all but impossible to crimp too much. Maybe more than needed, but supposedly not enough to be unsafe.
     
  10. HappyRoman

    HappyRoman Sherwood Forest Bronze Supporter Bronze Supporter

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    pull several rounds apart with a bullet puller/slam hammer.. look at the bullet, if there is a crimp/indentation you are probably there, another test is to try pushing by hand against a fixed surface, and see if the overall length changes, it should not.. 45 acp should measure 1.260" with a 230 rn bullet.
     
  11. trainwreck

    trainwreck salem Member

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    thanks guys when i get home this week ill take a look at the loads i have made.

    Thanks for the help.
     
  12. HollisOR

    HollisOR Rural OR, South of Dallas Active Member

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    Some other things to keep in mind. Case length effects consistency of the crimp. You will want all the cases to be the same length. Longer ones will have a heavier crimp. Shorter ones lighter. The greater the crimp, the greater the chamber pressures will be. To much crimp can bulge the case neck. If you are shooting a single shot, there is no need for a crimp. One of the best products on the market, is the Lee factory crimp die. Also, it is easier on the bullet to crimp on a different stage than bullet seating. Many bullet seating dies also do a tape crimp. Some will seat and crimp at the same time. Do that might effect the bullet shape. DEPENDS.

    A very light to No crimp will remove any case flare. (for bullet seating). On any jacketed bullets, do not crimp if there is no cannelure. A neat tool, is the case gauge. Basically a piece of round stock that is chambered for that round. On a finish bullet depending on gauge, the complete dimension can be checked (case plus bullet) or just over all case length.
     
  13. Shooter98

    Shooter98 McMinnville, Or. Member

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    Hey Trainwreck, just remember, if you're using Lee dies they recommend you DO NOT use a crimp die if your dies were made before 1986. The neck sizing dies takes care of this on all Lee dies after that date. It says this right on the front page of the instruction booklets that come with all Lee dies.
     
  14. chrislind2

    chrislind2 Springfield, Oregon Member

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    Love reloading, but crimping has scared me more than any other issue. I have read the Speer reloading book cover to cover and have read many other books over the years and often what helps the most is finding the reason for something. The why is often the best answer for how. I had an idea that crimping must be for how the bullet leaves the brass, and thought each caliber needed a certain crimp, which is true in some cases. The answer I found was that generally the reason for a good crimp is to prevent the bullet from being pushed back into the brass in particular when using the round in a semi-auto system. My understanding is that a light crimp is fine with a round that is used in a revolver, like .38 special, although some .38 bullets have a collar where a crimp would make a solid hold on the bullet. I was so convinced that even my 9mm needed such a tight crimp that I crushed 7 brass cases trying to over crimp. I have enough experience that I can "feel" when the crimp in probably correct, it was just a matter of not knowing how much crimp was enough. I'm getting better, and I'm finding that tons of experience are nothing without the proper knowledge to go along with it. Being comfortable with every reloading step makes it much easier and puts the fun back in.
     
  15. olydemon

    olydemon Olympia Active Member

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    What dies do you use? I recently learned the Hornady 3 die sets are Roll crim for 9mm and .45acp (probably .40/10mm too!). They are now offering their 3 die sets in Taper crimp, but no one has them yet. I called called Hornady and asked since Ive just started reloading and have been confused by the crimp. I load with the Lock and Load AP so I have an open spot if I wanted to get a lee Factory Crimp like alot of peopel do. Some of the old timers told me not to worry about the roll crimp and to just take the crimp to the point of removing the bell and thats it. So far my 9mm loads with just a light removal of the bell. I havent opened my .45 acp dies yet hoping to see some of the tapers on the shelf at Cabelas.

    One thing I read recently about crimp is that over doing it will dent the lead, but the brass will spring back causing the opposite of why your crimping.
     
  16. djthemac

    djthemac eugene Member

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    OP do you mind if i ask for your recipe? I just started getting into pistol reloads and I plan to get some Berry's 230 grain and 115grain
     
  17. deadshot2

    deadshot2 NW Quadrant WA State Well-Known Member

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    Before crimping, get a good understanding of "WHY" one needs to or shouldn't bother.

    Yes, crimping can be required in order to keep a bullet from moving. This will be dependent on the amount of recoil energy produced in the firearm and how the bullets waiting to be shot are held. If in a revolver cylinder, a moving bullet can cause the firearm to be jammed. In a tubular magazine, the "stack" can separate and when slamming back the bullets can be set back causing high pressures when those rounds are fired.

    Crimping can also be required for light loads and some powders to insure that all the powder burns completely, preventing secondary explosions in the barrel (usuallu with bad results).

    Some basic rules of thumb are:

    Revolver cartridges are finished with a roll crimp. Roll crimping requires equal case lengths in order to achieve uniform crimping. Short cases are under crimped if the die is set to not crush long cases.

    Autoloader cartridges are finished with a taper crimp and usually just enough to push the case mouth back to the bullet, removing any flare or bell that was added to ease seating a bullet.

    Rifle cases, unless fed from a tubular magazine like a 30-30, etc, are usually not crimped.

    Crimping can be done in the seater die in many cases but it takes a lot of trial and error as well as patience to accomplish properly. Too much roll crimp can crush a case and too much taper crimp can cause the case to headspace on the extractor rather than case mouth. Misfires are possible as well as deforming the bullet which doesn't add to accuracy.

    I prefer to crimp my autoloader rounds using a Lee Factory Crimp Die and do this as a totally separate step from bullet seating. It's easy to set up this way and the FCD also has a carbide ring in it that performs a final "sizing check" to make sure the case fully chambers and allows the slide to go fully into battery with no resistance.

    These are general rules of thumb and individual reloaders have been known to crimp for their own reasons. I crimp all my .223 rounds when using a cannelured round. Just my choice. Other reloaders don't crimp anything and claim no issues. The choice is up to the individual but the reasons for crimping still remain.
     
  18. olydemon

    olydemon Olympia Active Member

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    Always great info Deadshot!
     
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  19. Mikej

    Mikej Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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    Good reading here. I'm on the verge of getting into reloading, I have A LOT of once fired 9mm so that's my starting point, then maybe .45 and .38.

    The comment above ""Before crimping, get a good understanding of "WHY" one needs to or shouldn't bother"" is the best way for me to get anything, I always need to know WHY not just "That's the way it's done", as my reading comprehention is not so good I feel.

    Now all I need to do is get a reloader kit for a reasonable price. When that time comes I'll be looking for all the experts input.

    Thanks ahead of time guys!

    Mike
     
  20. noylj

    noylj high desert Active Member

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    1) you look at the case with a white background with bright light. Can you still see the flare/bell? If so, you need more crimp.
    2) is there a "shiny ring" around the case mouth? When you have the right crimp, you should see the bright ring from the taper crimp die working.
    3) feel along the bullet ogive. Your finger should easily slide over the case mouth, yet you can still feel the mouth. Try it after seating and before crimping. Your finger will catch on the flare/bell
    4) When you are setting up using an inert dummy round, disassemble the round after you think the crimp is good. Did you cut through the thin plating? Why are you using thin plated bullets when Montana Gold and Precision Delta jacketed are the same price? If the plating is damaged, you have excess crimp.
    5) Do what all the "modern" loaders do--take your calipers and try to measure the case mouth OD. Your crimp should be good at 0.470-0.472".
    6) work up various loads of 5-10 rounds each at a specific crimp setting and determine which is most accurate in your gun.