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crimp?

Discussion in 'Handloading and Reloading' started by JCools, Oct 9, 2010.

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  1. JCools

    JCools Member

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    Hello I have a Lee 38sp three die set.And was wondering if I have to crimp? The directions say (under bullet seating die). "If a crimp is desired,screw the die in slightly and test until the proper crimp is formed.Cases must be trimmed to the same length to provide a uniform crimp. Excessive crimp causes the bullet seater to deform soft nose bullets." BTW going to load some "hornady 125 GR HP/XTP. Then start casting my own.
     
  2. ArtP

    ArtP Member

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    You do need to crimp to keep the bullet from moving in the case under recoil, and handling too.

    It wasn't too long ago that I dealt with crimping myself for the first time as I had been doing rifle rounds only. IMO crimping takes the most effort to get right of all the steps involved. I too use the Lee three die set. I found by precisely setting the die depth in the press, it took all the guess work out of how much pressure to give on the downstroke. The shellholder coming up against the die determines where your stroke will stop and avoid crushing cases. You probably will crush a case or two in setting the right depth (an eighth of a turn matters), but once set you will be able to apply a consistent crimp with little guess work on your part. Because the die height is so sensitive, it does pay to have your cases exactly the same length.

    When I speak of die depth, I do not mean bullet seating depth. You have two depths to set, die and bullet depth. If I made no sense, ask and I'll clarify.
     
  3. JCools

    JCools Member

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    Thanks so I should I should seat all the bullets then adjust the die itself (tighter). Then
    run the bullets through again?
     
  4. ArtP

    ArtP Member

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    When everything is setup and adjusted, for me, one stroke seats and crimps and you can feel two distinct operations on one downstroke. Play around a little bit and you will learn to feel the difference in the amount of pressure necessary to first seat, then crimp. You will be able to feel when bullet seating stops and crimping begins.

    But getting the die adjusted right is a two step process.

    Pick five of your worst cases and a couple cheap bullets. Practice adjusting figuring you will ruin those chosen components. Feel free to use a bullet puller to disassemble and have another go at it. Just make sure you practice with unprimed/uncharged cases.

    I think this is one of the scenarios where you will learn more by practicing than I could write down for you. If you'd like I can post a pic of well crimped 44 mag loads. I'm sure you could get away with less crimp on a 38 sp, but you'd have something for reference if a web search doesn't turn anything up for you.
     
    Last edited: Oct 9, 2010
  5. JCools

    JCools Member

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    Thanks gonna play with it while U-M MSU game is on. Plus compare them to some factory loads.
     
  6. SASS#23149

    SASS#23149 Member

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    much much easier to get a seperate crimp die.Can be just another seat/crimp die with seater stem removed. because any time u change the crimp setting,the depth also changes with it.
    keeps the die cleaner inside because the bullet is always moving inward,and as it crimps it'll shave bullet material.
    adds a step if loading on a single stage,but worth it imho.
     
  7. rfwobbly

    rfwobbly Member

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    Mr Cools -
    • The outer part of the die (the body) sets the roll crimp.
    • The inner part of the die (the stem) sets the bullet depth. These adjustments are independent of each other.

    [​IMG]

    • Consistent roll crimp therefore is highly dependent on consistent case length.
    • There will be a groove (lead) or cannelure (jacketed) in the bullet for crimp placement. If your load manual tells you an OAL, then hitting the groove with the crimp is more important. Then the OAL becomes secondary and is only a guide.
    • Sometimes plated bullets from Berry or Rainier do not have a groove and so do not get a roll crimp. You have to buy a "taper crimp" die for those types of bullets. However, that is rare. Lee sells a separate taper crimp die for about $12.
     
  8. Border Hopper

    Border Hopper Member

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    Taper crimping is one option that you might consider for bullets without crimping cannelures. I shoot non-cannelured .38 Spl. lead bullets in a SASS lever gun, so I use a Lee taper crimp die (marked .380) to maintain the proper Cartridge Over All Length (COAL) and function in a very finicky and sensitive rifle. Works so well that I crimp the same way for my pistol loads, with a lighter lead bullet.
    My SASS loads are not wimpy. I chronograph my ammo, do the math, and run right at the 254 footpounds that used to be the "standard .38 Spl., 850 fps 158 graim load". I never have to dig into the bottom of my cart to find the heavy hitters for knockdowns. I'm already shooting a working load.
    My SWC and JHP loads are roll crimped, 'cause they are loaded nearer the redline, and I use two dies to accomplish the desired effect.
     
  9. Steve C

    Steve C Member

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    Best way to set the crimp is:
    1. Insert the die and screw the seating stem in far enough so that you get no crimp and seat a bullet to the length you want. Note that you shouldn't use a full throw of the operating handle but just push the bullet in with small pushes and checks until its seated to the proper depth, for revolver bullets its when the case mouth is at the middle to top of the cannelure or crimping groove.
    2. Back out the seating stem so it will not push the bullet in any further and with the case and uncrimped bullet run all the way up, screw the die body in until it contacts the mouth. Back the ram out a bit and screw the die in maybe 1/4 turn, bring the ram back up to crimp the case mouth. Check the cartridge and see if the crimp is suitable and what you want, (I usually want it to look like a factory round). Adjust the die in small increments if more or less crimp is desired and lock it down when you get what you want.
    3. Run your now loaded and crimped case back into the die and turn the seating stem in until it stops on top of the bullet. Lock it into place and you are good to load ammo with that particular bullet.
     
  10. JCools

    JCools Member

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    crimp

    Okay think I got it,but if the top of the case is= to the top crimp groove its okay?
     
  11. ArtP

    ArtP Member

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    Steve wrote you a fantastic set of instruction.

    There should be a tiny amount of travel at the end of the stroke that lays on the crimp. You'll feel it.

    This is not set in stone, but the case mouth should end about 2/3 up the cannelure after crimping (33% of the cannelure still visible). Some prefer it a little different.
     
  12. Border Hopper

    Border Hopper Member

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    You are getting the best knowledge around. With this above info, a set of calipers, a few reloading manuals and the raw materials at hand, go do it and see what your newly loaded and crimped rounds do in your gun. Remember to change only one variable at a time, comparing an uncrimped load to a crimped load with the same COAL and the same charge of the same powder and the same primer, etc.
    Remember that roll crimping (and belling of the case mouth) will shorten the life of the brass case. Splits are more common with roll crimping, but reasonable inspection of fired (and clean) cases shows the problem. Roll crimping is also very popular for magnum rounds and heavy bullets and slower powders.
    Don't get too wrapped up in the TV while you reload. Your attention to detail is very important to you and your family.
     
  13. 243winxb

    243winxb Member

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    Crimping Info from Lee's

    From link below >
    :)
     
  14. Seedtick

    Seedtick Member

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    JCools, you've been given plenty of good info here.

    There is a sticky at the top of this forum that is a great aid (with pictures too) in all things crimp. There's been a lot of time and work put into it and it shows. Thanks to all who have contributed to it.

    In case you've missed it here is a link.

    How much crimp? Lee FCD guidance sought.

    HTH

    ST

    :)
     
  15. rfwobbly

    rfwobbly Member

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    In fact, you probably owe us all a beer. :D
     
  16. JCools

    JCools Member

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    Thanks guys, as for that beer RF, its a long way to Atlanta from Detroit so I guess I'll just have to pass all this knowledge on. Again thanks loaded about 100 rds since U-M got their buts handed to them was easy to stay focused on reloading.
     
  17. ArtP

    ArtP Member

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    You aren't going to post the verbal results or a picture? Like our help is trivial? Help me understand I'm mistaken.
     
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