throat/neck tolerance question

Discussion in 'Gunsmithing' started by eshorebwhntr, Apr 14, 2013.

  1. eshorebwhntr

    eshorebwhntr Well-Known Member

    Apr 11, 2009
    I've got a 7stw that was custom built by gtr. He requests a dummy round when building the gun. I was a novice to long range shooting and reloading at the time and loaded my dummy round with Remington brass. This yielded a case with a .313 neck and that was what my throat was cut to.

    Since that time stw brass has been hard to find so I went about fire forming some from norma 300 h&h brass. I've used a .310 neck bushing when I resized before but noticed today when I was reloading the fire formed brass that I had almost no neck tension because the Norma brass is thinner walled than the Remington.

    Based on what I've measured the new wall thickness is .010, x2 is .020, +.284 is .304.

    So my question is will having a separation of .009-.010 between the neck/throat hurt or effect anything from what I've been use to with the very tight fit?

    Thanks in advance for any advice.
  2. Coyboy

    Coyboy Well-Known Member

    Jan 30, 2005
    your accuracy shouldn't suffer with new load development, but brass will work harden quicker so you will need to anneal every 2-3 firings to keep necks from splitting.