Dark case necks

Discussion in 'Reloading Forum (All Calibers)' started by uncle-buck, Dec 11, 2018.

  1. uncle-buck

    uncle-buck

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    Have been using an AMP annealing machine and it seems like the necks of some cases are darker than normal.
    Is it possible for the machine to malfunction and over-anneal?
     
  2. dkhunt14

    dkhunt14

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    Are they all fired the same number of times? Are they the same brand? Are some dirtier then others? You can send cases in and get them checked if unsure. Matt
     
  3. Zero333

    Zero333

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    If possible, post a pic or 2 of the case necks.
     
  4. PatMiles

    PatMiles Gold $$ Contributor

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    I polish the necks of my brass every time before I anneal with my AMP. The idea is to polish all the muck-muck off so it doesn't get baked on by the annealing.
    Don't know if this might be associated with your dark necks, just food for thought
     
  5. uncle-buck

    uncle-buck

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    That's probably what's happening. Burnt powder residue is getting baked on. Thanks
     
  6. kvd

    kvd Silver $$ Contributor

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    As a final step before priming, polish them in corn cob media with a dab of metal polish until even the annealing discoloration is removed. Run them long enough and they will shine like new pennies - inside and out! Another benefit of this final polishing will be that seating smoothness will be much improved.

    6mm BRA.jpg
     
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  7. Ccrider

    Ccrider Silver $$ Contributor

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    How do you clean them before loading to get the residue off.
     
  8. Ggmac

    Ggmac Gold $$ Contributor

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    The usual way . it's a lot easier and safer than polishing after its loaded .
     
  9. milanuk

    milanuk Team Savage Gold $$ Contributor

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    I've had a little bit of this happen... tumble in corn cob, then anneal, lube, size... and the necks look a bit darker than before. I'm guessing a bit of burnishing may be going on... Nothing changing dimensionally that I can tell, not like it really matters beyond aesthetics.
     
  10. Webster

    Webster

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    Small traces of chemicals on the neck/shoulder area can create big color changes. Give a few cases a light polish by hand with 0000 steel wool and wipe off with isopropyl alcohol. I think you will see less color change.
     
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  11. Hammer47

    Hammer47 I suffer fools poorly. Silver $$ Contributor

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    Sounds like your torches are adjusted too close to the case neck, back em off a bit and see if the darkening disappears.
     
  12. milanuk

    milanuk Team Savage Gold $$ Contributor

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    What torches? ;)
     
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  13. kvd

    kvd Silver $$ Contributor

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    After FL sizing, ultrasonic cleaning - usually two 30 minute cycles will almost entirely remove the carbon residue inside the case and the primer pocket residue using Hornady One Shot® Ultrasonic case cleaning solution mixed up at about 2.5% by volume. Annealing is next (AMP), and then corn cob vibratory polishing with a few drops of Flitz Tumbler Media Additive. The tumbling is anywhere from 3 hours to overnight (if I forget to turn it off). Overnight will definitely polish off the discoloration from annealing but this is purely cosmetic. The real benefit in my mind is the smoothness of the bullet seating step. The polishing with the Flitz additive gets rid of the "grabbiness" from just ultrasonic cleaning alone.
     
    Last edited: Dec 13, 2018
  14. deadduck357

    deadduck357

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    That's what I do before annealing.
     
  15. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    If you dont rinse a citrus based polish off real good they turn beautiful shades of purple and blue
     
  16. PatMiles

    PatMiles Gold $$ Contributor

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    Farm out man!
     
  17. stifffingers

    stifffingers Gold $$ Contributor

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    I don't have to worry about the darkening of necks. To start I brush inside of neck and steel wool outside, decap without sizing, then I anneal. Next I wet tumble witch removes all coloration, then size because I want the cases to have a slight coating of Imp. wax left on the case to impede any tarnishing. There are many that believe tumbling with stainless steel pins will work harden the cases. That is not true, according to Alex Finnley at AMP. He posted on the FAQ page that the cases are only surface hardened and it does not harden any further when tumbling.
     
  18. kvd

    kvd Silver $$ Contributor

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    There are many ways to achieve the same end and one is probably as good as another. I have used stainless steel pin tumbling and, other than beating up the case month a little, find this method works great to clean up cases. Agree that any work hardening is superficial and of no concern. Through rinsing in clean water and fast drying really helps to mitigate water spotting and discoloration as it does with ultrasonic cleaning. I switched over to ultrasonic cleaning because it does almost as good a job as SS pin tumbling and is faster. After tumbling and as a final rinse I've also used a 0.1 molar solution of benzotriazole in water with a little 90% isopropyl alcohol for corrosion protection. Works great to prevent the brass from tarnishing but so does the Flitz polish. To each his own. My 2¢
     

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