0.02" expansion on 264 WM brass

Discussion in 'Reloading' started by 112Savage, Feb 14, 2013.

  1. 112Savage

    112Savage Well-Known Member

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    Nov 12, 2011
    The difference in base to shoulder from my old fired brass to new virgin brass is 0.02" . To the best of my knowledge the chamber is headspaced correctly from the base to the belt, and 0.02" is not that far in the world of fireforming. However, my question is can I run my normal load of 68.5 grains of Retumbo in this virgin brass without having problems?

    The brass is prepped and weight separated 7mm Rem Mag brass necked down to 264". When I was necking down I sized the brass down until I saw where the chamber quit scratching the unsized brass. My bullet is in the lands, so I believe the cartridge is properly supported by the belt and the bullet. So will my brass suffer with full power loads?
     
  2. woods

    woods Well-Known Member

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    Jun 4, 2006
    IMO no

    .020" is not unusual in a belted case and most of my guns average that

    Here is an extreme case

    Factory ammo
    [​IMG]

    Once fired
    [​IMG]

    That's almost .040" and probably would have reached that in a couple more firings

    That rifle got rebarreled because IMO there would have been too much initial stretch at the pressure ring even if subsequently headspacing off the shoulder. On all of my other belted case guns that average .020" I haven't had any problems with case head separations or anything else.
     

  3. 112Savage

    112Savage Well-Known Member

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    Nov 12, 2011
    Thank you, I know I've never had any problems with factory ammo, but just worried a little. Should I expect less accuracy than headspacing off of the shoulder and less total case capacity?