Really need some help understanding....

Discussion in 'Reloading' started by rsbhunter, Apr 23, 2011.

  1. rsbhunter

    rsbhunter Well-Known Member

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    Ok, i'm new to using neck sizing dies that use bushings. If a chambers neck dia is .298, as in the 6.5x284 Win. and the Norma 6.5x284 is .300...(per another post) why is the new brass neck dia , both lapua 6.5x284 and Rem 260 measuring .291 loaded? Everything i read , and all of the help i have gotten says to neck size .002 under a loaded rnd.s od neck dia.That figures out to sizing the neck around .009-.011 each time......is this the norm? Some have said no, but alot of what i read shows these #s (.298 neck chamber) as the spec....been in this game awhile, and i'm STILL learning new facts every day!!!!! Thanks for any help....rsbhunter
     
  2. sp6x6

    sp6x6 Well-Known Member

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    Someone more knowledgable will chime in. I dont have a bushing die,but I check my shot brass, neck = .371[ call it chamber] but there must be some spring back or it would be stuck, but you do similar on shoulder bump. My sizer takes neck to .365 factory die,if I was to use a bushing it would be .363. My loaded round is.366. My norma brass has been cosistant and most of my loads are within .001 concentric with forester sizer and sleeved micro seat. My #'s sound lower, but I DONT know my chamber spec. 338 Norma.
     
  3. backwoods83

    backwoods83 Well-Known Member

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    A SAAMI spec 6.5x284 norma/win chamber will measure .297-.298 depending on the make of the rifle, if the neck of one of your shot cases measures .298 you should try to get away with a .294 bushing but you may only have 10-15lbs neck tension and that isn't enough, then you'll want to use a .293 and that should bring it up to about 25lbs which is fine. You should always try not to work your brass no more than .004-.006", it wears it out to quick. I have a .296 neck and use a .292 bushing, it works great. Good luck.
     
  4. rsbhunter

    rsbhunter Well-Known Member

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    backwoods83, Thanks for the help...there must be alot of difference between Rem and Lapua brass....miked the 6.5x284 loaded with a Berger 140 VLD and it is .294..which is about perfect...the rem brass for the 260AI is mikeing at .291...i am looking into getting some lapua 260 brass, or neck down 7/08 or 308 brass to get thicker neck material....rsbhunter