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Thread: New to 30 BR - Robinnett case specs

  1. #1
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    New to 30 BR - Robinnett case specs

    HI everyone. I have experience with 30 BR and .308 but none with 30BR. I have a spanking new Shillen 1:17 twist with Robinnett 30BR chamber.
    I have been looking on the net for case specs for this caliber without any luck.
    Question: How long is this case supposed to be ? Would 1.5" be reasonable trim length ?
    Thanks ,

  2. #2
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    Type "Robinett reamer" ...

    in the Search box in the upper right and you can spend the rest of the week reading posts about "Robinett" specs. Good luck.

  3. #3
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    Oct 2019
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    ask the guy that CHAMBERED THE BBL!

  4. #4
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    That exact question is a big one
    Randy has posted about the confusion of all the “Robinett” reamers out there and the method you use to form your brass is critical in a good fit to your chamber

    So you really need a reamer print from whoever did the work or a chamber cast

    Good info here Randy shared

    http://forum.accurateshooter.com/thr...posed.3933398/

  5. #5
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    this thread might help.


  6. #6
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    Quote Originally Posted by danyboy View Post
    HI everyone. I have experience with 30 BR and .308 but none with 30BR. I have a spanking new Shillen 1:17 twist with Robinnett 30BR chamber.
    I have been looking on the net for case specs for this caliber without any luck.
    Question: How long is this case supposed to be ? Would 1.5" be reasonable trim length ?
    Thanks ,
    The industry standard for the 30BR has settled in on a .330 neck, zero freebore, and trim to length of 1.500 to 1.510.

    Since Randy kinda invented this concept, those reamer specs have become known as the Robinette.

    But there other 30BR reamers out there. Call your gunsmith.

  7. #7
    Join Date
    Nov 2006
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    ME
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    You should have

    or can get from the reamer maker, a reamer print. That will give you the specifications of your chamber, like length, freebore amount, throat angle, etc. Check you reamer spec. I trim my cases about .005" short of my 1.52" chamber length.

  8. #8
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    May 2010
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    Drummondville, QC, Canada
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    30BR case spec

    Quote Originally Posted by rsmithsr View Post
    ask the guy that CHAMBERED THE BBL!
    I just sent an email to the BC outfit that got it made by an Oregon company. Didn't think there would be so many variants in this Robinett chamber !

  9. #9
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    May 2010
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    Drummondville, QC, Canada
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    30BR case spec

    The more I read these answers to my topic, the more I think I didn't form the cases as well as they should be. Here's how I formed them.
    I used the first forming die of an RCBS .308 to BR forming set of dies, which brings the shoulder back to where the BR case shoulder starts at. I cut the extra 1/2" from the excedent of the neck length. Then, I turned the necks to .325" OD, neck thickness of .10", FL sized with 308 x 1.5 RCBS die, trim length to 1.5". Loaded case neck is .327".
    32 grains of H4198 comes to the top of the neck, no room for the bullet, even with a 18" drop tube.
    I probably should have waited after fireforming before trimming the length.
    I requested a reamer print from ther dealer who got it chambered.
    I really appreciate all the help I am getting from the members of this forum.
    Thanks
    Last edited by danyboy; 05-27-2020 at 04:51 PM.

  10. #10
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    dannyboy:

    Respectfully, making 30BR cases from 308W is not only doing things the hard way but will almost certainly result in chambering/sizing/extraction issues.

    Get some Lapua 6BR cases and make your life sooooo much easier!

    Good shooting. -Al

  11. #11
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    May 2010
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    Drummondville, QC, Canada
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    [QUOTE=Al Nyhus;835284]dannyboy:

    Respectfully, making 30BR cases from 308W is not only doing things the hard way but will almost certainly result in chambering/sizing/extraction issues.

    Get some Lapua 6BR cases and make your life sooooo much easier!

    Good shooting. -Al[/QUOTe
    Chambers well, extracts well . pretty sure much easier than enlarging 6 mm neck . only drawback is having to turn .018" from necks. I will make this work. Just a matter of time and patience.

  12. #12
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    Quote Originally Posted by glp View Post
    or can get from the reamer maker, a reamer print. That will give you the specifications of your chamber, like length, freebore amount, throat angle, etc. Check you reamer spec. I trim my cases about .005" short of my 1.52" chamber length.
    Greg, THE problem: which reamer print?!!? If the smith cannot/will not say, one needs a new smith!
    Sadly, some appear to have not a clue . . . to quote Bob Dylan - again - "the times they are a changin' . . . "RG

  13. #13
    Join Date
    Oct 2019
    Posts
    186
    well go look at all the steps you used to get you there.
    all the time and money spent.
    fire form a 6br case in the chamber( no bullet, fast pistol powder), trim and turn.
    duh
    you made this way too hard, and did you get your 308 cases with small primer pockets ??

    [QUOTE=danyboy;835287]
    Quote Originally Posted by Al Nyhus View Post
    dannyboy:

    Respectfully, making 30BR cases from 308W is not only doing things the hard way but will almost certainly result in chambering/sizing/extraction issues.

    Get some Lapua 6BR cases and make your life sooooo much easier!

    Good shooting. -Al[/QUOTe
    Chambers well, extracts well . pretty sure much easier than enlarging 6 mm neck . only drawback is having to turn .018" from necks. I will make this work. Just a matter of time and patience.

  14. #14
    Join Date
    Mar 2020
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    Third Tomb of Chritianity
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    41
    [QUOTE=rsmithsr;835293]well go look at all the steps you used to get you there.
    all the time and money spent.
    fire form a 6br case in the chamber( no bullet, fast pistol powder), trim and turn.
    duh
    you made this way too hard, and did you get your 308 cases with small primer pockets ??


    Lapua .308Win Palma for example.

    No headspace variation in the "no bullet,fast pistol powder" method, depending on extractor claw/rim thickness play ?

  15. #15
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    Quote Originally Posted by R.G. Robinett View Post
    Sadly, some appear to have not a clue . . . to quote Bob Dylan - again - "the times they are a changin' . . . "RG
    Amen, buddy.

    Like Bill Murray's hapless character in 'St. Vincent', there are shooters that need Dylan's 'Shelter From The Storm' of clueless plumbers. -Al

    https://www.youtube.com/watch?v=YVHqTF203_0

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