Finding distance to the lands, weird issue.

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  • Finding distance to the lands, weird issue.

    Hey loaders.
    I hit a snag while trying to determine the length to land's in my x-bolt 30-06.
    I used a method i read about on the net where you neck size an already fired case so the proj only just slides in and out of the case but with a little resistance.
    I chambered this dummy round, extracted and measured 5 times to be sure.
    The average measurement was 3.2890".
    This is where im confused, in my loading manual(lee) and on the adi data they list the minimum COL for 180Grn pills and ar2209 as 3.300"
    The measurement i took is smaller than the minimum listed in the data.
    As far as i understand seating the proj further in than minimum causes pressure problems.
    Please help me understand this, ive been trying to get my head around it for days now and sadly Google is of no help lol.

    Cheers

  • #2
    hit a snag while trying to determine the length to land's in my x-bolt 30-06.
    I used a method i read about on the net where you neck size an already fired case so the proj only just slides in and out of the case but with a little resistance.

    ADD a littel more resistace pill is slipping in might look here
    http://www.6mmbr.com/catalog/item/1433308/977259.htm

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    • Guest's Avatar
      Guest commented
      Editing a comment
      Try seating a bullet long, then seat lower and lower until the resistance disappears then work back up a smidge until you get tiny marks on a fresh bullet from the rifling.

  • #3
    Originally posted by Lead Slinger" post=7926
    Hey loaders.
    I hit a snag while trying to determine the length to land's in my x-bolt 30-06.
    I used a method i read about on the net where you neck size an already fired case so the proj only just slides in and out of the case but with a little resistance.
    I chambered this dummy round, extracted and measured 5 times to be sure.
    The average measurement was 3.2890".
    This is where im confused, in my loading manual(lee) and on the adi data they list the minimum COL for 180Grn pills and ar2209 as 3.300"
    The measurement i took is smaller than the minimum listed in the data.
    As far as i understand seating the proj further in than minimum causes pressure problems.
    Please help me understand this, ive been trying to get my head around it for days now and sadly Google is of no help lol.


    Are you sure you have the right length, my winmag is 3.285" with 180gr??
    Here is a video that migt help. I use the hornady OAL Gauge.
    http://www.youtube.com/watch?v=9OZ8u8e7mSc

    Mark

    Cheers
    Tikka T3X 6XC
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    • #4
      Regarding reloading manuals, a listed 180g bullet COAL doesn't fit all. Different bullets have different ogive shapes and therefor will seat differently when your getting specific with them.

      Correct me if I'm wrong, but an X-bolt 30.06 is a hunting rifle I think.
      A hunting rifle should have a longer leade/jump. They don't want bullets getting stuck in barrels.
      I thought you'd have trouble trying to touch the lands if anything.

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      • #5
        Yep the x-bolt is a hunting rifle.
        So i treid the method from spadger and i got.
        3.3360 will not chamber(too tight)
        3.3250 chambers but is tight
        3.3200 will chamber smoothly
        however i cant see any marks on the proj from the lands.


        Cheers

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          That cleaning rod method on Pitty's video is pretty much what I do. Hacksawing a case never worked for me.

          Fittings for the cleaning rod can be improvised 1) a loose patch on a jag that is screwed on tight. Grind the tip of the jag flat. The patch will centre the rod. 2) a bulldog clip on the rod, up against the muzzle.
          Good Luck

        • Guest's Avatar
          Guest commented
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          Originally posted by Lead Slinger" post=8064
          Yep the x-bolt is a hunting rifle.
          So i treid the method from spadger and i got.
          3.3360 will not chamber(too tight)
          3.3250 chambers but is tight
          3.3200 will chamber smoothly
          however i cant see any marks on the proj from the lands.


          Cheers
          once you close the bolt, lift it up and down a few times, it should rotate the round enough to notice some scoring. remember your OAL may differ from round to round due to bullet dimentions. 3.3200 would be a safe starting point if you cant quite get to the lands messurment, your playing with miniscual messure and it can be frustrating for everyone

      • #6
        The Vid was good and worth keeping -- I find this stuff a bit of a guess and see and the cleaning rod method is next to fool proof as all it needs is a soft and consistent touch to work.
        The hacksaw method and slightly sized necks always leave a bit of doubt.
        I find the depth of my chamber by sizing a case and then inserting a flat base projectile in backwards also works well - after machining off the radius of the base.
        I use a variety of projectiles in 308 and this will sort out all the different ogive problems.
        The tools to fit a cleaning rod are easily made from a drilled piece of ally bar stock and a little lock screw / tab bolt is easy enough to add.
        New to reloading though I know the basics well enough --very informative TNX.
        Good post blokes
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          Thanks all.
          Your god's amongst men.
          I have fired the 200 previous loads without any issue's.
          I just used a field tip from an arrow and ground the tip flat, this actually screwed into the cleaning rod. Worked perfectly.
          Ill load 10 rounds at 3.257 and see how it goes.
          Cheers

      • #7
        Lead Slinger #12
        Your 3.287" is for your rifle and that bullet, alone. Reduce it by 0.030" so that the bullet will not be touching the rifling and you are good to go. The fact that you have been firing with the bullets seated touching the rifling, means 1) that the powder charge is not so heavy that pressures signs are evident
        and 2) that the previous 200 rounds were not so long that the bullets were jammed in the rifling, or you Might have had trouble extracting an unfired round.
        3) If you want, you could increase powder charges in 0.3 grain increments, if you think you want more velocity. Watch for pressure signs and note the effect on group size.
        Point of impact might change too with the shorter overall length.

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        • #8
          Does anyone use a candle to get some soot on the bullet to see the land contact points? (uncharged case with a fired primer of course). An old timer told me about this method and I tried it, the soot works very well and shows up the most minute contact areas.

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