Flash hole uniforming

dcso3009

February 13, 2005 17:39

I have been trying various tricks with the primer pocket and flash hole and have a question...
Is there a problem with cutting on both sides of the flash hole? What I did was to cut a little from both the primer pocket and from inside the case. I tried it with a low power load in my 30-06 A-Bolt with great results.

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  FrancF

  February 13, 2005 18:15

  Perfect!
  Thats the same as I do, Just kiss the flash hole on the primer end if its egg shaped a slite chamfer is all you need. a few Thou. goes a long way. IMHOP
  
  
  NRA Life Endowment Member

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  JustC

  February 13, 2005 18:15

  are you referring to deburring the flash hole? if so this is a benchrest trick from way back. I do it to every lot of brass I prep.
  
  why chase the game when the bullet can get em from here?....
  Got Balistics?

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  FrancF

  February 13, 2005 18:22

  Justin- sounds like he is doing front and back- Its a great trick, old, but it works! as you said.
  
  
  NRA Life Endowment Member

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  ContacFront

  February 13, 2005 18:24

  Cut front and back? Never seen or heard of that.

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  FrancF

  February 13, 2005 19:01

  OK-
  In other words, he is cleaning up both ends of the flash hole. The powder side (Unless its premium brass) will have a burr. The primer side can be egg shaped, thus causing irregular ignition. So if you take the step to clean up the front an back side of the flash hole, the more uniform your ignition will be.
  
  Most important! You do Not want to enlarge the flash hole, just make it round.
  
  Think of it as just deburring a hole on both ends. Maybe someone out there has a graphic that will explain it better.
  
  
  
  NRA Life Endowment Member

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  rimfire72

  February 13, 2005 20:34

  I do the inside of the case,but never thought about doing the primer side. I'll have to give that a try.
  
  

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  dcso3009

  February 14, 2005 02:50

  Thanks guys. The results were quite surprising. Like I said in a plinking load for my '06 it shaved almost 0.25" off the groups. Unfortunately my gun does not like light bullets and was shooting about 7/8". Now I will try it with my hunting loads, since that is what I use that rifle for.

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  FrancF

  February 14, 2005 15:37

  If anyone is confused about it, I will do a drawing on the subject.
  
  
  NRA Life Endowment Member

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  Ray Boone

  February 14, 2005 17:31

  I hadn't trimmed the primer side of the hole; but did "deburr" the powder side. This helped some though I don't have any group measurement to quantify the improvement. I've read thta the best groups will be optained if the hole is centered, of the same diameter in opening and thickness, so if I'm going to get an accurate rifle, I probably should start working the cases over.

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  lcflcf

  February 19, 2005 08:39

  I have a question, I bought a deburring tool and do the inside but, But how do you do the primer side, My tool won't fit in the primer pocket, Thanks Les

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  FrancF

  February 19, 2005 17:30

  lcflcf
  
  
  Thats beacuse you can't with the tool you are using. let me post a pic so you can see.
  
  
  NRA Life Endowment Member

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  FrancF

  February 19, 2005 18:07

  The picture is crappy, But this the tool for deburring/chamfer the flash hole on the inside of the case. Then you use the same tool to give a slite-"just kiss it chamfer" Nothing more! to the flash hole on the primer side.
  
  
  [img][/img]
  
  Now Not to make this confusing, I also use a "Center Drill" To make the flash hole uniform. It is a little larger than the one shown.
  
  
  NRA Life Endowment Member

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  lcflcf

  February 20, 2005 06:18

  Thanks FrancF, I got the picture now, Les

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