Why 6 BRA?

Discussion in '6BR, 6BR Improved & Wildcats' started by Curious, Oct 28, 2017.

  1. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    You know @tom could answer that better than me. He's pretty good at keeping notes.
     
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  2. Nature Boy

    Nature Boy

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    Or the Manzier

     
  3. Grimstod

    Grimstod Machinist, Designer, and Shooter. Gold $$ Contributor

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    You i have been thing this in my head since i first heard it called the Bro
     
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  4. BT1

    BT1 Gold $$ Contributor

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    Just checked the lands on my first bra and they moved a total of 0.004 after approximately 400 rounds. Have not shot too many 10 shot strings but shooting LG 5 shot strings in about 10 to 12 seconds. Compared to several Dasher barrels that move almost twice that.
     
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  5. Grimstod

    Grimstod Machinist, Designer, and Shooter. Gold $$ Contributor

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    Would you say the longer neck is the cause of this or just using a smaller amount of powder?
     
  6. BT1

    BT1 Gold $$ Contributor

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    Likely a bit of both. Steve
     
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  7. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    Count me in the latter. I believe barrel wear is a function of heat and duration, aside from barrel attributes. I may be wrong but all I've seen in regard to this is theoretical. I would like to be proven right or wrong by something more scientific, though.
     
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  8. Terry Altom

    Terry Altom Silver $$ Contributor

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    I agree with you for sure. For me, it's easy to make sense out of both views. I'd like to see a real study by metallurgical standards tell us the truth.
     
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  9. tom

    tom Gold $$ Contributor

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    Chuck,

    As it relates to throat advancement (lands touch point), yes it is slower growth with the BRA. As it relates to the barrel seeming to loose a step, I couldn't give an answer with any certainty. It seems when I get a good barrel, with either chamber, it will shoot, stay shooting, stay in tune without changing the load every day, stay shooting for over 1000 rounds, stay shooting even if the throat advances 2 thousands in every relay, stay shooting even if I screw up.

    When I don't get a good one, they tend to shoot really good on Friday, but sometimes forget what their job is on Saturdays and Sundays, and seem to loose whatever edge they had 500-700 rounds.

    I can keep all the notes in the world, but each one is individual. Seems the last couple years I've been seeing them lose it sooner. The first BRA did a little better, but it seems to have lost a bit towards 900 ish rounds.


    Tom
     
  10. JohnMill

    JohnMill Gold $$ Contributor

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    Now you're just being sirry
     
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  11. 4xforfun

    4xforfun Gold $$ Contributor

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    Stirring the pot....but......since brass is considerably softer than steel, and the melting point of brass is considerabley less, also, wouldn't we see erosion in the brass necks?

    Tod
     
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  12. Sheldon N

    Sheldon N Silver $$ Contributor

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    Wouldn't the erosion be spread out over all pieces of brass? If you had 100 cases, the amount of erosion in any one case would be 1/100 of the amount of throat erosion?
     
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  13. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    Im not an expert on how a throat erodes. However I picture it like an oxy/acy torch effect. Cant cut brass with a torch, but you can melt it. Either way, throats do move slower in the BRA, not that thats very important to me. Its all about accuracy and agging ability. Thats why Im such a fan of the case. All you have to do is chamber 50 dashers and 50 BRAs and get the feed back. It will be clear as day.
     
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  14. 4xforfun

    4xforfun Gold $$ Contributor

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    Maybe.....but you didn't take into account that brass is much softer and has a much lower melting point, which means it should erode much faster than BBL steel. So, that 1/100th = ....What?

    Tod
     
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  15. Raythemanroe

    Raythemanroe Bullet Whisperer

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    Then again, brass isn't getting to temps a barrel does running ten - twenty rounds in a few minutes.. Well, unless you are a fast reloaded..


    Ray
     
  16. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    ...and won't all of that abrasive powder that hits the neck, at the "convergence point", make the necks really thin? Better stop cutting "thin to win", and make them thick as a brick. No need to anneal...Brass hasn't been work hardening....It's been losing neck tension as it wears thinner. Just drop down on bushing size and sell the annealer.

    Ya'll help me out here. I'm running out of ideas that support the theory of shoulder angles and neck lengths saving barrels. Lol! Who knows? Maybe they're right but I'm gonna keep believing that heat and duration are the main culprits..until they test some 180° shoulders. Now THAT just might save barrels. Lol!
     
  17. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    Convergence point is one idea. Barrel life is so far down the list of things I think about I dont have a firm opinion on it either way. All I know is they do move slower in the BRA than a dasher, I doubt its the 1.2 grains less powder making the difference but who knows.
     
  18. tom

    tom Gold $$ Contributor

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    Or better yet, someone figure out WHY it shoots better. I know it's not strictly capacity because I've been there before and went right back to dashers.

    Tom
     
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  19. Grimstod

    Grimstod Machinist, Designer, and Shooter. Gold $$ Contributor

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    My Guess is that because it has a longer neck the donought zone is far enough back that bullets do not get seated into it. Mike Ratigan attributed this cause alone to be the reason the 6PPC shoots so well.
     
  20. Grimstod

    Grimstod Machinist, Designer, and Shooter. Gold $$ Contributor

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    I have seen a lot of loaders that do. They just do not know any better. BRA is dummy proof ;)
     

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