300 WM 208 AMAX neck tension issue

Discussion in 'Reloading' started by Weston, May 13, 2015.


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  1. Weston

    Weston Well-Known Member

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    I can't seem to get enough neck tension with my new 300 WM. I'm seating the bullets (208 A MAX) at the furthest I can to still fit in the TIKKA T3 magazine, which is right at 3.365" COAL. My issue is that there is hardly any neck tension and I'm having to use a crimp to secure the bullets. the bullets do not seat by hand and I'm thinking that it is seated pasted the bearing surface. I can push the seated bullets into the cartridges fairly easily, which I am not a fan of. Has anyone run into this before? I would assume at .020 over published max coal of 3.340 (hornady) I would have had enough bearing surface to hold a production bullet. Am I mistaken?
     
  2. Weston

    Weston Well-Known Member

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    I just tried some berger 210 VLD's which have no issue being seated to .010 shorter than mag length.
     
  3. Weston

    Weston Well-Known Member

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    One more update before bed, I had prepared the brass FL sizing all of them (brand new norma) and had been achieving said results with the LEE die, however, after using the Lee neck die I have no problem seating either bullet with adequate tension to even much deeper seating. Any idea's on this? I have never needed to use a neck sizing die before and am still confused as why the berbers would be seating fine without it but the A-max are not.
     
  4. dragman

    dragman Well-Known Member

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    What do you necks measure?
    After sizing?
    After bullet seated?
    And fired?
    Just to eliminate some possibilities. Because of shape the begets might have the bottom of the bearing surface in the neck and the AMAX might not.
     
  5. AZShooter

    AZShooter Well-Known Member

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    First thought that popped into my head is that the 208s are a smaller diameter. Some strange stuff happens sometimes. Measure several of each brand of bullets and compare.
     
  6. jsthntn247

    jsthntn247 Well-Known Member

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    Sounds to me like your expander button in your fl die is a little too big and causing the necks to open up too much(over bullet diameter). Two things you can do is 1. get a better die than the lee. 2. Take the decapping stem out and polish the expander button down in small increments until you get the desired tension. When I fl resize I use Forester fl dies so I can order different sized expander buttons and play with neck tension.
     
  7. phorwath

    phorwath Well-Known Member

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    This would be my first guess as to the source of your problem. IF this is the problem, then this is also my first recommendation to resolve the problem.

    If one reloading die enables sufficient neck tension, and another reloading die doesn't, then presuming you're reloading the very same brass cases, the problem is with the reloading die, and not the bullets.
     
  8. Weston

    Weston Well-Known Member

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    Which is what I was thinking. However, it's strange to me that the neck tension is fine with the bergers even with the full length sizing. Also, I can't hand seat either bullet, and if I seat the amax a hair longer (with just FL sizing) it holds it just fine, which leads me to believe that the bearing surface on the Amax may be too deep.
     
  9. phorwath

    phorwath Well-Known Member

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    You might want to place a few of your A-Max bullets between the two jaws of your calipers in order to confirm that the base of the bullets at the junction where the boat tail merges with the bearing surface body isn't a larger diameter than the rest of the bearing surface.

    I had a box of Nosler Accubond bullets years ago which had a larger diameter at the junction of the boat tail and the bearing surface than the diameter of their bearing surface forward of that junction. I called Nosler and they replaced that box of bullets and said something about their bullet forming die may have been out of spec, or worn out of spec over time.

    Those Nosler Accubonds would spin around freely between the jaws of my calipers, only making contact with the jaws at the boat tail/bearing surface junction. This condition will, of course, expand the brass case necks more than necessary as the base of the bullet is pressed/seated into your case necks.
     
  10. MagnumManiac

    MagnumManiac Well-Known Member

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    Are you using a Lee collet type neck die and then switching to a non collet FL die?
    I am confused as to what you are doing exactly.
    What do you mean by 'hand seating' your bullets?
    I doubt very much that the bullets will be out of spec, I have used the same bullet in my own F-Class rifle, the 208 A-Max was quite accurate in my rifle.
    Have you measured your case necks before and after seating the A-Max's?
    I would be purchasing a Redding 'S' type bushing die, whether it's a full length or neck die is up to you, but this is my set up, Redding body die, Forster FL comp bushing die and Forster comp seating die and a Redding 'S' type neck bushing die that I use to size brand new unfired brass to my predetermined neck tension on NEW brass, this changes as the amount of firing and annealing takes place, neck tension changes as the hardness of the brass changes. I anneal every sizing on my comp brass. This is different to NEW unfired brass and needs a different bushing size to have the same neck tension, according to my test equipment.

    Please answer the above questions so we all can have a better understanding of what's taking place.

    Cheers.
    gun)
     
  11. Weston

    Weston Well-Known Member

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    I had initially just FL sized all the brass (new) trimmed to spec, tumbled to remove lube and then loaded. I have measured the bergers at .3080 compared to the amax at .3075.
    Now when I could not get the Amax to hold without a crimp I decided to try to run the brass (which had already been full length sized, though the lee collet neck sizing die I have, which then provided sufficient neck tension to hold the Amax. As far as "hand seating" I attempted to see if the bullets could be forced into the case neck without using a press, which they couldn't, regardless of the die.
     
  12. Weston

    Weston Well-Known Member

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    For anyone interested, I contacted hornady and informed them of my issue, the tech measured some of their bullets in the same lot (2150396) and came up with the bullets being out of spec. apparently the spec is +- .0003 and these were .0005 too small.
     
  13. AZShooter

    AZShooter Well-Known Member

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    Well what do ya know, this time I got it! I have only encountered undersize bullets once in over 30 years. With a host of posters trying to help you, one of us should get it right.

    Hope Hornady switches the bullets out for you.
     
  14. Weston

    Weston Well-Known Member

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    Yup, I'm glad I got all of the info from everyone, certainly nice to to have a resource to go to for things I'm less than knowledgeable about!

    Hornady was great about the switch and have emailed me an RMA label already.