Finally got to shoot my 6br N I built. Few questions please.

Discussion in '6BR, 6BR Improved & Wildcats' started by MrBottleneck, Aug 27, 2017.

  1. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Well, today I finally got to shoot my 6br I built using a Rem700 receiver (was stock .243) and Criterion 1n8 Remage barrel.
    I must say I am very happy with just breaking it in today. Groups where great (off bipod) for putting together a light load of 29gr of Varget seated at 1.772ogive (.010 off) in Lapua brass using Berger 105 Target vlds. One pictured measures about .3
    We picked up a scope yesterday at a Cabelas (Leupold VX3i 8.5-25x50) it was also something I was happy with as the glass is very clear for the $850 I paid. I would rather had moa but, mil is ok as it will be also used for longer range shooting.

    My question comes from my primers I used today. I didnt have a chance to pick up any CCI450 or BR4s so, I used what I had which was CCI400s.
    I noticed some primer cratering (see picture).
    Will going to magnum 450s help due to the harder cups or is that not the case?

    image.jpeg

    Anyhow I loved the way it shot and non existant recoil. I think once I really get to a decent load its really going to be a shooter.
    Here are a few pictures of my build, qload info from todays load, a average group from todays shoot at 100yrds (1" orange dot) and 5 shots of same load run through my V3.
    image.jpeg image.jpeg image.jpeg image.jpeg
    Thanks for any input or other suggestions.
     
    Last edited: Aug 27, 2017
  2. JamesnTN

    JamesnTN Silver $$ Contributor

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    You need your firing pin bushed and the pin turned down. He hold of gretan rifles and have him fix your bolt.
     
  3. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Interesting so, that is the issue not the primer choice?
    So, was I in danger of piercing a primer or is that just a little flow from the bigger pin and hole?
    I was wondering what the deal was as I was sure 29gr was way under max.
    Oh, well I suppose if thats the deal I must address it. Should I not shoot it until fixed by Greg?
    I appreciate you jumping in and giving input. :)
     
  4. snert

    snert Gold $$ Contributor

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    Might be better with harder primers, but bushing will stop it regardless. hate to see a pierced primer and pocked boltface for no good reason. Gretan will take care of it quick.
     
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  5. MarkS

    MarkS Silver $$ Contributor

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    The 450 or BR4 may help some. A lot of people think it is pressure, but it if the firing pin. You can shot as is, just don't go up much on your load. I have shot 6BR for a long time with a crater like your's. The 6PPC will do the same thing. The 6BR is a high pressure round, they like it hot. It needs the firing pin bushed.

    Mark Schronce
     
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  6. JamesnTN

    JamesnTN Silver $$ Contributor

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    You can keep shooting but why? Call Greg Monday and ship him your bolt. Most likely you'll have it back in about 10 days. Also don't fall for the lightened firing pin. Keep the standard weight firing pin.
     
  7. tclaunch

    tclaunch Silver $$ Contributor

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    How did you find out about that???
    :)
     
  8. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    If it bothers you, have the boltface bushed. 450s and br4s will help. Truth is cratering does not hurt anything, it just bothers people. And chances are your pin is fluted from the factory. Most of the new ones are. You can switch to a full weight pin and that will help as well, along with a 24lb spring. Its not because of a sloppy fit, its a diameter thing, so by going to a smaller pin the primer cant push the pin back into the bolt face. Get a Kelbly action with the .075" pin and it will crater too. Only an issue if it bothers you.
     
  9. JamesnTN

    JamesnTN Silver $$ Contributor

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    Several thrown matches, time on the phone with you, measuring everything, more time on the phone with you. And bam out of the blue you said never use the high speed firing pins. Lightbulb went off that's exactly what I did. The rifle was a 1.7 agging and after the firing pin and spring change it wouldn't shoot under 3". Sent it back had it swapped back out for a full weighted pin and it went back to shooting.
     
  10. tclaunch

    tclaunch Silver $$ Contributor

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    When you been there, done that, advise is much easier to come by. Lol!!

    Another fine lesson taught me by Mr. Dwight Scott.
     
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  11. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    James you said have the firing pin turned down but, later in post #6 you say dont fall for the lightened firing pin.
    Wouldn't turning it down lighten it?

    So, I reckon its the to bush or not to bush thing going on.
    I suppose since I am new to the 6br it was just something I was not expecting to see.
    I suppose since the radius is still round on the cup I could watch the grains as I work up for pressure and disregard the cratering.
    Will it crater to the point of piercing (of course I am talking within reason)?
    I might see what just running 450s or BR4s seem to do. Then send it off to Greg when winter sets in.
    Doesnt bother me just not expecting it. :) Thanks for the input fellas.
     
  12. Terry Altom

    Terry Altom Silver $$ Contributor

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    My Remington Dasher cratered most primmers and pierced federal with lite to mid range loads.
     
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  13. JamesnTN

    JamesnTN Silver $$ Contributor

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    The firing pin that strikes the primer is turned to like .062. A lightened firing pin has been fluted might near the entire length of the pin. Where a standard pin is solid. I still have the fluted pin I'll take pics and post so you can see the differences.
    Besides pitting the bolt face if you pop a primer you can also break a trigger. Ask me how I know that one.....
     
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  14. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Ok, got ya. Some pics would be cool. This is dealing with the unknown on this whole small primer and bushing the bolt etc.
    Was wondering about that whole lightened fire pin deal.
    Thanks its appreciated. :)
     
  15. Big Mc

    Big Mc Gold $$ Contributor

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    I am like Alex . If you get hartburn with it. Fix IT. But if you don,t It hurts nothing..
     
  16. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Nah not to worried about it as its not pressure.
    Shot again today using two different loads.
    Both loadeds dimensionally the same. Berger 105 VLDs coal 2.350 coal 1.772 ogive (.005 off). Lapua brass but, CCI450 this time.
    1. 29gr Varget best I could do was about in 4s
    2. 32gr Win760 very good groups. Several groups in low 2s
    Both shot bipoded up.
    The 450s helped a touch on cratering.
    Left one is from last week using 400s Right one is a 450 from today.
    image.jpeg

    image.jpeg
    Thanks for everyones input. :)
     
  17. FJIM

    FJIM

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    well I would for sure use CCI 450's. I had a 6BR on a old hart action and it cratered primers for years..I pounded it till the bolt was hard to open and never blew a primer. You are getting the cratering due to the firing pin hole not excessive pressure it will even do it if you back the load off. I also have a 6XC on a rem 700 and using reformed Palma brass with the small primer it craters also. You can shoot it like that or have the bolt bushed..Now if the case sticks to the bolt when you open it and you have to pick the case off the bolt face now you have excessive pressure.
     
  18. 6xcshooter

    6xcshooter

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    plus one on that. I've only had 1 bolt bushed, it worked, needed??? by the way dang near all remington factory bolts will crater primers at usable pressures. I go by extractor marks for pressure indication.
     
  19. mr.big

    mr.big

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    +1 ,,if you do blank a primer and scar your boltface you will have to have it done anyway plus if you are using a Jewell trigger it will need to be sent back and fixed also,,,
     
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  20. Drop Port

    Drop Port

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