Neck turning strategy - just want to double check

Discussion in 'Reloading Forum (All Calibers)' started by MikeMcCasland, Mar 20, 2020.

  1. MikeMcCasland

    MikeMcCasland Gold $$ Contributor

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    I'm about to turn 500 pieces of new Lapua 308 brass, and wanted to make sure I'm not crazy.

    My plan was to dip the necks in motor oil, run them over the mandrel, and toss them on the neck turning lathe.

    My turner (powered 21st lathe) has the ability to turn into the shoulder, but since the brass is new and the shoulders not consistent, I figured I'd just turn them by sight, stopping short of the shoulder.

    Given the current state of affairs I don't really want to waste the componets to fire the brass before I turn them. I'd rather get it out of the way now.

    Anyone see any issues with this? If you do it, does it cause you any problems getting inconsistent AZTEC codes from your AMP?

    Thanks,
    Mike
     
  2. 47WillysGuy

    47WillysGuy Gold $$ Contributor

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    My process is the same for new unfired or fired cases:
    -Anneal all cases
    -Trim all cases to required length (Ensures the cut into the neck is the same for each case)
    -Chamfer each neck ID (Removes burrs from case necks)
    -With die neck expander removed, Full Size all cases squeezing case necks to minimum.
    -Lube all case necks prior to expanding.
    -Expand case necks prior to cutting (5ea at a time).
    -Lube turning mandrel with a couple of drops of lube.
    -Cut the necks to desired thickness.
    -Clean up cut with 0000 steel wool. (Gets rid of the cut finish and smooths out the neck...)

    Note: Going from 0.015" thick neck to 0.011" neck thickness should be done in 0.001" increments, unless your just doing a clean up cut.
    Note: Heat is your enemy. Go slow, I won't do but 10-20 case neck cuts in an evening.
    Note: Be judicious with the lube oil, if it get into the case interior and it doesn't get washed out, you'll have kernels of powder sticking to the case neck and case interior. Don't ask me how I know that. LOL!
     
  3. dskogman

    dskogman Silver $$ Contributor

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    You could just get a no turn neck and not worry about it ;)
     
  4. rsmithsr50

    rsmithsr50

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    wellll
    try this
    resize all with a fl/bushing die under size the neck a little
    trim to length
    deburr
    lube inside of neck
    run over expander
    rough cut
    resize neck re-expand
    final cut
    clean lube off
    you should neck size before loading
     
  5. MikeMcCasland

    MikeMcCasland Gold $$ Contributor

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    Hah, I've got plenty of clearance.

    I've also got plenty of time as of late, so I'm pulling out all the stops in the misguided hope it'll make a difference in my scores.

    We're turning necks, and weighing primers here at the McCasland compound; real exciting stuff!.

    Edit: Just finished the first 100.
     
    Last edited: Mar 20, 2020
  6. bozo699

    bozo699 Gold $$ Contributor

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    I wanted to reply but chose to keep quiet but I turn my no turn necks also Mike! Even Lapua isn’t perfect but it’s close with skim turn and even if I don’t shoot better I feel better
    Wayne.
     
  7. 1shot

    1shot Silver $$ Contributor

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    All my brass gets turned, even the no turn chambers. I'm set up to do this operation fairly quickly, I believe it is an aid to consistency and I like turning brass! No down sides for me.

    Lloyd
     
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  8. PopCharlie

    PopCharlie Silver $$ Contributor

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    You will need to analyze a neck turned piece of brass. IME, the AMP Aztec code will be different.
     
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  9. TrxR

    TrxR

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    I'm going to be turning 100 pieces of 6br brass into 30br. I'm assuming I got to expand before trimming to length as they will get shorter from the expanding? Then I'll turn from there?
     
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  10. mikeeg02

    mikeeg02 Michael Glantz

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    I'm not sure how much your taking off, but now that you've done your "bulk" cut, (though I'd do the rest at that setting first) I would adjust your turner to skim another tenth off, and do maybe 5-10 an evening. Or every few hours. But not any sooner between sessions. If you wait long enough and do it right, you'll see the difference when you do the skim cut. Some cases you'll take a skim, some it wont touch at all, some it will touch in spots. It will be a real eye opener. Just that little bit of heat put into the turner, can change how much you take off. Were talking tenths, which doesn't sound like much, but it does show up on paper.

    IMO there's a huge benefit to having two cutters. One set for the initial cut, and one set for the skim cut. For repeatability sake.

    I realize this may sound ridiculous, but were all on quarantine anyways, what better do you have to do than to learn something. If you're seating bullets with hand dies, you will notice a difference in seating pressure consistency.
     
  11. 47WillysGuy

    47WillysGuy Gold $$ Contributor

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    Wow! 100 case neck cut in 4 1/2 hours. BTW, how much off the neck were you cutting? Is your neck thickness consistent throughout the 100? Are you within 0.0005 for all cases?
     
  12. Mulligan

    Mulligan Gold $$ Contributor

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    dropping the turner in a bucket of ice-water between cases will go a long ways to help with uniform neck thickness.
    CW
     
  13. MikeMcCasland

    MikeMcCasland Gold $$ Contributor

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    This batch of Lapua brass has necks at .0147-.0152ish.

    I'm taking them down to .014.

    As far as accuracy, they're pretty accurate so far as I can tell. I'm using a Mitutoyo ball mic, however I have trouble getting perfectly consistent readings from it even with nothing on the gauge. I'm using as consistent a force as I can, and going 3 clicks every time.

    On the brass, I'm usually within .0002-.0003 though.

    I don't know if it matters, but this is a 21st powered lathe, with only one speed (21st motor), so that may speed things up a bit. I'm doing two passes. I basically run the brass on there very slowly, not moving the case forward on the cutter until it's stopped removing material. I do the same operation when backing the cutter off.

    Once off the mandrel I'll knock the shavings out of the cutter, and run it back through just to make sure I got everything.

    I'll take a video, and you guys tell me if I'm doing something dumb.
     
  14. 4Bowhunter

    4Bowhunter

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    Please send me a pm and I’ll send you my number and we can talk about your turning process.
     
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  15. mikeeg02

    mikeeg02 Michael Glantz

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    You wont be able to measure with a ball end mic the difference that is there. Thats why I said a second cutter set just a tenth more, will show you the variance you have. Ive tried with a ball end mic, and thought I was good too, but when seating bullets Id find a couple that were different. Hence the quest and why I do things the way I do now. Ultimately its up to you on how far you want to take it. I dont care what cutter you have, the same problem exists. Big George Kruchinsky was adamant I did things the way I described, and I learned why. If you take just enough to skim on the second cut, you will too.
     
  16. Jdne5b

    Jdne5b Gold $$ Contributor

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    How do you manage surface friction when seating? I find that makes a big difference, and probably enough to hide neck thickness variation.
     
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  17. mikeeg02

    mikeeg02 Michael Glantz

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    After my standard brass prep from fired, I clean the inside of my necks with steel wool, then dip them in graphite spray in a little cup(I actually use the lid). Then wipe the excess off the outside and let them dry. So that variation has been removed as much as possible. I also do that before expanding and turning.

    EDIT: I also measure pressure ring diameter before seating them.

    blaster-car-fluids-chemicals-8-gs-64_1000.jpg
     
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  18. rsmithsr50

    rsmithsr50

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    DO NOT MIC THE BRASS,
    MIC WITH A BULLET SEATED.
     
  19. MikeMcCasland

    MikeMcCasland Gold $$ Contributor

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    I just spoke to Phil for a bit. I think I'm on the right track.

    Once these matches start up again we're gonna be in business for real. ;):D
     
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  20. Bc'z

    Bc'z Gold $$ Contributor

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    Great thread Mike! A lot of great info to be gleaned for us novice neck turners

    Hows that GT40 running?
     
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