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Should I Outside Neck Turn My Brass?
October 25, 2018 voltage

Should I Outside Neck Turn My Brass?

By Paul Box


This is a question we get just about every week. Should I neck turn my brass? Well, the answer can be yes….and no. Let’s look a little deeper into it.

Naturally, if we had our favorite gunsmith chamber a rifle with a “fitted” neck we’ll have to neck turn in order for it to fit our chamber. But what about a standard SAAMI spec chamber? This all depends on the quality of your brass. Namely your case neck thickness variation. What I do is take a ball Mic and check the case neck thickness at “8:00 o’clock, 12:00 and 4:00 o’clock points. If my thickness variation is .001” or less, I wouldn’t outside neck turn. Unless we’re shooting 1,000 yd. benchrest I don’t think you’ll see any difference in accuracy if this thickness difference is any smaller than that.

Our main goal in outside neck turning is to give our seating die it’s best chance to seat a bullet with good concentricity with as little of run out as possible. This puts our bullet in better alignment with the center of the case body and in a squared and trued action, more perfect alignment with the bore.

Brass that has a neck thickness difference that’s more than .001″can be turned down to this spec and will shoot fine. They’ll also have the advantage of not being too thin, which will give early case neck splits and short case life.

Comments (2)

  1. Frank Haertlein 6 months ago

    Outside neck turned some once fired Lapua cases in a 22-250 Ackley Imp, big mistake. My groups opened up to more than 2 inches at 100. The un-turned, once fired cases produced ragged one holers once I reached the Accuracy Velocity of the barrel (http://www.orionite.com/accuracyvelocity.htm) . Do not turn case necks unless you have really bad brass and even then this is an iffy proposition. If your cases are so bad that you need to neck turn them you are better off throwing them away and going with quality produced brass.

  2. Chuck 6 months ago

    What is a good case concentricity gauge. Most of my stuff is RCBS but Im not married to them.

    Thanks
    Chuck
    Lewiston, MI

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