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    • #33788
      redriverhunter
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      I got a rifle that was bored out to 358 win. I slugged the barrel and the reading i get is 350, it has three groves. now I take the slug and it will not go into a sized case which reads .356. any suggestion on how to get a good reading on my bore diameter thanks

    • #33789
      Harter
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      Use a soft RB or lead fishing sinker and drive it down a lubed barrel . It should start at least as large as the largest expected groove diameter . Odd numbers of lands are different to measure but a modern 35/38/9mm cal should be no less than .355 and no more than .359 groove . I suspect that your .350 dimension is the bore and not the groove diameter . There is a process for measuring odd land slugs but I haven’t used it so I can’t remember it’s description .

      That’s my presumed knowledge level bit as a casual reminder/refresher . I can’t imagine a 35 cal barrel being a .350 groove with a proper chamber and nobody notices . Even a solid pilot 9mm match reamer wouldn’t fit in the barrel . It might be possible with a floating pilot but , ummmm , inattentive to ones tools or possibly just plain old screwed up . Maybe it was a rebore for and 8.5 or a 348 ? I can’t think of an 8.5 and I have no idea what the dimensions of the 348 are so that’s just pitching sand in the wind to give benefit of the doubt to someone in the chain .

    • #33792
      Goodsteel
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      You cannot get a good reading on odd number grooved barrels. JES three groove is usually spot on though Size your bullets to .360, expand your necks to .357 and go in piece.

    • #33795
      Larry Gibson
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      Cut a strip from a soda or beer aluminum can 3/8 x 3″. Mic the thickness. Wrap it around the slug and pinch tight on one side. Hold it tight and mic diameter. Subtract twice the strip thickness……that will give you the groove measurement…..close enough anyway.

      Better to do a cast or slug the throat and size to that.

      Larry Gibson

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