Results 1 to 14 of 14

Thread: squaring heads

  1. #1
    Join Date
    May 2006
    Posts
    197

    squaring heads

    does any one do any thing to the heads of the 6 mm br or the 6mm ppc?
    gary

  2. #2
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    9,577
    One guy that useta' post about it here on BRC was the late Skip Otto a BR Icon. Skip recognized that it was an important part of the vibration/accuracy equation and he'd turn his on the lathe.

    I believe in fire-forming them square instead.

  3. #3
    Join Date
    Jun 2010
    Location
    USA
    Posts
    492
    Quote Originally Posted by alinwa View Post
    One guy that useta' post about it here on BRC was the late Skip Otto a BR Icon. Skip recognized that it was an important part of the vibration/accuracy equation and he'd turn his on the lathe.

    I believe in fire-forming them square instead.
    I've done both ways - I'm with Al - 55-60K PSI squares 'em pretty well.RG

  4. #4
    Join Date
    Feb 2003
    Posts
    1,417

    Thumbs down No, don't do it.

    Squaring case heads with a lathe or wilson case trimmer is not only unnecessary but if overdone can even be detrimental or in an extreme case could even be dangerous by weakening the solid case head.

    I'll admit to being one who has tried it in my younger days but after thirty years of trying to separate the fly poop from the pepper, I no longer waste the time. During my early years of BR group shooting, I placed great emphasis on keeping everything neat, clean, polished etc. Now I do only what I know from experience makes a difference; no more. Life's too short.

    If you bisect a Lapua 220 Russian case, you find that the solid head is .160 deep. The bolt face on most actions is .150 deep and you need a minimum of .005 clearance from the bolt nose to the coned breech. If you sketch it out and add it up you find there is only .005 of the solid head that's up into and supported by the chamber. This puts you right at the border line of having unsupported case hanging out of the chamber. Turn off .004 to .005 squaring the case heads in a lathe and you reduce this to zero.

    Consider also that if you remove .002 or .003 from the case head that reduces the depth of the primer pocket by the same amount. But of course you can correct this by running the primer pocket tool in again but why bother when you can simply skip all this time consuming stuff and enjoy more shooting time instead of case prepping.

    For what it's worth.

    Just ol' Gene Beggs blowin' smoke again.

    Best regards to all and good shootin'!

  5. #5
    Join Date
    Feb 2003
    Location
    Tennessee
    Posts
    6,375
    Quote Originally Posted by Gene Beggs View Post
    Squaring case heads with a lathe or wilson case trimmer is not only unnecessary but if overdone can even be detrimental or in an extreme case could even be dangerous by weakening the solid case head.

    I'll admit to being one who has tried it in my younger days but after thirty years of trying to separate the fly poop from the pepper, I no longer waste the time. During my early years of BR group shooting, I placed great emphasis on keeping everything neat, clean, polished etc. Now I do only what I know from experience makes a difference; no more. Life's too short.

    If you bisect a Lapua 220 Russian case, you find that the solid head is .160 deep. The bolt face on most actions is .150 deep and you need a minimum of .005 clearance from the bolt nose to the coned breech. If you sketch it out and add it up you find there is only .005 of the solid head that's up into and supported by the chamber. This puts you right at the border line of having unsupported case hanging out of the chamber. Turn off .004 to .005 squaring the case heads in a lathe and you reduce this to zero.

    Consider also that if you remove .002 or .003 from the case head that reduces the depth of the primer pocket by the same amount. But of course you can correct this by running the primer pocket tool in again but why bother when you can simply skip all this time consuming stuff and enjoy more shooting time instead of case prepping.

    For what it's worth.

    Just ol' Gene Beggs blowin' smoke again.

    Best regards to all and good shootin'!
    Hey old Fat Albert pilot...hows tricks?

    (Fat Albert=Boeing 737.)


    /

  6. #6
    Join Date
    Jun 2010
    Location
    USA
    Posts
    492

    Thumbs up DITTO all of this.

    Quote Originally Posted by Gene Beggs View Post
    Squaring case heads with a lathe or wilson case trimmer is not only unnecessary but if overdone can even be detrimental or in an extreme case could even be dangerous by weakening the solid case head.

    I'll admit to being one who has tried it in my younger days but after thirty years of trying to separate the fly poop from the pepper, I no longer waste the time. During my early years of BR group shooting, I placed great emphasis on keeping everything neat, clean, polished etc. Now I do only what I know from experience makes a difference; no more. Life's too short.

    If you bisect a Lapua 220 Russian case, you find that the solid head is .160 deep. The bolt face on most actions is .150 deep and you need a minimum of .005 clearance from the bolt nose to the coned breech. If you sketch it out and add it up you find there is only .005 of the solid head that's up into and supported by the chamber. This puts you right at the border line of having unsupported case hanging out of the chamber. Turn off .004 to .005 squaring the case heads in a lathe and you reduce this to zero.



    Consider also that if you remove .002 or .003 from the case head that reduces the depth of the primer pocket by the same amount. But of course you can correct this by running the primer pocket tool in again but why bother when you can simply skip all this time consuming stuff and enjoy more shooting time instead of case prepping.

    For what it's worth.

    Just ol' Gene Beggs blowin' smoke again.

    Best regards to all and good shootin'!
    Especially the the bold! RG

  7. #7
    Join Date
    Feb 2003
    Location
    Houston, Texas
    Posts
    7,039
    Quote Originally Posted by g n brezinski View Post
    does any one do any thing to the heads of the 6 mm br or the 6mm ppc?
    gary
    Been there, done that, but for a different reason.

    Back in the mid '2000's, Lapua produced a run of cases that had a convex face. I discovered it because after continued firings, (in the upper load window), primer pockets started getting so tight that you would crush primers trying to get them in. A weird phenomenon no doubt.

    I made a fixture to face the Heads flat on a 220 Russian Case and the problem disappeared.

    We obviously don't have that problem now.

    As far as accuracy is concerned, Randy is correct. 50,000 psi does a good job of squaring things up.

  8. #8
    Join Date
    Feb 2003
    Posts
    1,417
    Quote Originally Posted by JerrySharrett View Post
    Hey old Fat Albert pilot...hows tricks?

    (Fat Albert=Boeing 737.) /

    Hey Jerry! I had forgotten the early 737 was nicknamed 'Fat Albert.' I came to have great respect for them.

  9. #9
    Join Date
    Sep 2003
    Location
    Gastonia, NC
    Posts
    862
    Hey all you old guys stop telling these young guys what not to do. Let'em consume vast amounts of time piddling over nothing. If they're hunkered down messing with brass they won't be on the range practicing.

  10. #10
    Join Date
    Apr 2008
    Location
    Cloudcroft, NM
    Posts
    623

    Do the reverse

    Quote Originally Posted by jackie schmidt View Post
    Been there, done that, but for a different reason.

    Back in the mid '2000's, Lapua produced a run of cases that had a convex face. I discovered it because after continued firings, (in the upper load window), primer pockets started getting so tight that you would crush primers trying to get them in. A weird phenomenon no doubt.

    I made a fixture to face the Heads flat on a 220 Russian Case and the problem disappeared.

    We obviously don't have that problem now.

    As far as accuracy is concerned, Randy is correct. 50,000 psi does a good job of squaring things up.
    Jackie,

    Now if you can put the proper amount of convex back into the case head, your loose primer problem with the new softer brass will disappear.

    Michael

  11. #11
    Join Date
    Feb 2003
    Location
    Poetry, Tex.
    Posts
    6,100
    Quote Originally Posted by Dave Tooley View Post
    Hey all you old guys stop telling these young guys what not to do. Let'em consume vast amounts of time piddling over nothing. If they're hunkered down messing with brass they won't be on the range practicing.
    Yup Dave, let them keep chasing their tail.

  12. #12
    Join Date
    Dec 2006
    Location
    Branchville, NJ
    Posts
    448
    I have a know it all young engineer here at work, who is weighing powder to .01gr, but is then loading it into untouched Lake City factory primed brass. He wonders why he isn't getting any good groups.

  13. #13
    Join Date
    May 2006
    Posts
    197

    ppc

    thank you for the reply .i know now that i am chaseing my tail.but not shooting a lot of br and asking ? i find is the only way to get a good answer from all of you br people.
    gary

  14. #14
    Join Date
    Feb 2003
    Location
    Texas Panhandle
    Posts
    1,846
    Quote Originally Posted by Gene Beggs View Post
    .....

    If you bisect a Lapua 220 Russian case, you find that the solid head is .160 deep. The bolt face on most actions is .150 deep and you need a minimum of .005 clearance from the bolt nose to the coned breech. If you sketch it out and add it up you find there is only .005 of the solid head that's up into and supported by the chamber. This puts you right at the border line of having unsupported case hanging out of the chamber. Turn off .004 to .005 squaring the case heads in a lathe and you reduce this to zero.
    ...
    Just ol' Gene Beggs blowin' smoke again.

    Best regards to all and good shootin'!
    That's so on a Remington and was why back in the 80's when Bob Brackney wrote his article about bushing the bolt face for a PPC and installing a Sako extractor in Rifle magazine that he recommended cutting back the bolt nose for a .125" deep bolt face and then setting up the bolt nose to barrel recess clearance to .001". Of course, that was when we were using the balloon head Sako .220 Russian brass. All the custom benchrest actions followed suit and have .125 deep bolt faces as well. So, with the current custom actions, you have a lot more case head in the barrel than you would if you were using a standard Remington bolt. We can stand a little more clearance from the bolt nose to the barrel cone now just because we no longer are shooting the balloon head .220 Russian brass.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •