The value of a headspace gauge

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  • RC20
    Senior Member
    • Oct 2014
    • 174

    #16
    FC are the heaviest. From memory of 205 gr.

    RP the next, something around 195 gr.

    I like RP a lot, it seems to be in between soft and hard, lasts well etc. Opinion and feeling, I can't prove it.

    Military is down in the 185 or 190 gr.

    FP is very soft, I think (opinion) it would fire form better, its also throw away as I have yet to be able to keep it more than about 8 rounds even with carful shoulder setup (based on the fired shoulder not any default dies setup.

    Along with my brother, we have measured something like 12 Model of 1917s. All were about the far end of field reject, all shoot just fine.

    As they are military we accept them for what they are and have fun shooting them.

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    • fguffey
      Senior Member
      • May 2012
      • 684

      #17
      Along with my brother, we have measured something like 12 Model of 1917s. All were about the far end of field reject, all shoot just fine.
      And no one has a clue as to why? A bunch of smiths got to gather and found someone to blame it on. This stuff does not lock me up and I find no reason to make up stories, for me it is not challenging, if I have a rifle with a long chamber I form cases to fit. For most that is a complicated process because they only have cases available to them that manufacturers make available. I purchases cases that have been fired in long/trashy old chambers, when culling the cases at the range I cull the cases, I only purchases cases that are long from the shoulder to the case head. I use the length of the case from the shoulder to the case head to off set the length of the chamber.

      I noticed you did not list the length of the chamber in thousandths, you only mentioned field reject gage. I have a M1917 that has a chamber that is .016" longer than a minimum length/full length sized/over the counter/new round; what does that mean? It means a new factory over the counter round has .016" clearance between the shoulder of the case and shoulder of the chamber. If I fired cases that were go-gage length from the shoulder to the case head I would have .011" clearance. But, because this stuff does not lock me up I use 280 Remington cases, when sizing the 280 Remington cases I adjust the die off of the shell holder .014" with a feeler gage and then size the case. After sizing and trimming I load and then chamber the case, after chambering I have the magic .002" clearance between the shoulder of the case and shoulder of the chamber. I have asked many times where did the magic .002" come from? Almost all reloaders respond with "I bump...."

      .016"? Reloaders believe the case has head space, they believe .016" is too much head space and the case will have case head separation. And then I say the shoulder on my 30/06 cases do not move when fired in my M1917 and none of them understand what I am talking about.

      F. Guffey

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      • RC20
        Senior Member
        • Oct 2014
        • 174

        #18
        The head space thing has gotten to be quite the myth. I have done a standard write-up that I think it clear.

        If the headspace is too long the gun won't fire. Shell moves forward with the firing pin hit and simply won't shoot.
        If its marginal (per SAMMI) then it will fire fine, blow the case out and if you do a minimum shoulder bump back you have a fire formed case that is fine.

        303 had generous head space and chambers. You cant reload it more than 3 times, it does not kill anyone.

        If its too short no new brass will fit. Self fulfilling you can't shoot it

        In between its also not an issue.

        You get better accuracy with fire formed to the chamber and minimum bump back but I suspect that's under 1/2 MOA
        All my 1917s push the very limit of field reject. They just get their own brass.

        Comment

        • fguffey
          Senior Member
          • May 2012
          • 684

          #19
          [QUOTE=RC20;508345]The head space thing has gotten to be quite the myth. I have done a standard write-up that I think it clear.

          If the headspace is too long the gun won't fire. Shell moves forward with the firing pin hit and simply won't shoot.

          I have done a standard write-up that I think it clear
          You think it clear? I have always said there are a lot of events that happen between pulling the trigger and the bullet leaving the barrel reloaders simply do not understand. "If it is too long?" Meaning the chamber from the shoulder to the bolt face? And you done a standard write=up?

          I chambered a round in a rifle, I pulled the trigger and the bullet left the barrel. I ejected the case, the case was ejected with just a hint of a neck, the shoulder on my case did not move. I could ask "What does that mean"? Because of the failure of the reloader to understand the events between pulling the trigger and the bullet leaving the barrel asking the question "what does that mean" is a wasted effort.

          The case that was ejected with the hint of a neck: I moved the shoulder on a chamber forward .127" forward meaning I increases the distance from the shoulder to the bolt face .127": After increasing the length of the chamber I chambered a case that was shorter from the shoulder to the case head (minimum length/full length sized case in the long chamber, closed the bolt and then pulled the trigger.

          The case, bullet, powder and primer did not out run the firing pin, the case did not move and because of this miracle the case head did not move from the bolt face. My firing pin busted the primer before anything took off for the front of the chamber. I know that is what happened, the case proves the case did not take off for the front of the chamber. I do not make this stuff up; reloaders believe they can move the shoulder back, they believe they can bump the shoulder back. I can't, it all goes back to reloaders not understanding what happens between pulling the trigger and the bullet leaving the barrel.

          F. Guffey

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