Necks

Discussion in 'Reloading' started by Cruizin, Jan 29, 2007.

  1. Cruizin

    Cruizin Well-Known Member

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    Dec 25, 2006
    Ok question for you. I recently bought a K & M neck turning device and carbide insert for my 243 AI and it removed some donuts on the inside of the case and took the high spots off. I use redding bushing style dies for it and would like to have a little better control of the bushings needed. It looks like now I need to buy a neck thickness measuring tool and while I'm at it I might as well have something that can measure concentricity. I use a forester co-ax so I'm thinking my run out should be pretty good but it would be nice to check it.

    What tool would you recommend for measuring neck thickness and runout? The sinclar tool for measuring runout looks nice and will do all cases without having to have separate pilots. Some of those neck thickness guages are spendy...
     
  2. wapiti13

    wapiti13 Well-Known Member

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    Mar 8, 2004
    Cruizin, After you resize you case and seat the bullet, you mic the outside of the necy to determine the correct bushing for a Redding die. Depending on how much bullet tension you want, you then order a bushing usually .002-3 smaller than the size you measured. You can adjust tension as required with different bushings. I just saw a thread where someone was going .004 and got better groups. You just need to experiment with your set up. If you measure the before and after firing neck width, you can see how large your neck is. You usually need .002+ to release the bullet correctly and not get a jammed case in a hunting rifle. Benchrest shooters go tighter. Compare the two measurements and see if you have enough release. Usually, a good mic will do the job. A concentricity gauge is a good tool, but not needeed to answer your question. /ubbthreads/images/graemlins/smile.gif
     

  3. Michael Eichele

    Michael Eichele Well-Known Member

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  4. Ballistic64

    Ballistic64 Well-Known Member

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    Dec 21, 2004
    Cruizin, these are the tools Im using to measure my necks and runout.Before I had the Mitutoyo mics I made due with a good quality dial caliper and it can be done accurately,but the mics sure are nice to have.The concentricity guage is a Holland.I didnt go with it for any other reasons than its solid and uses no plastic parts,its probably a little harder to turn the case in the fixture than the Sinclair though.

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  5. robbor

    robbor Well-Known Member

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    Jun 12, 2003
    you should not need to buy a neck mic. #1 your K&M turner has an attachment for a dial indicator so you can use that for neck thickness. #2 in just trimming the high spots off if you bushing doent resize the necks then you can resize in the FL resizer and you should be able to measure after seating a bullet just like you should have origionally done for your bushings.