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  1. #1
    Join Date
    Jan 2009
    Location
    NW Iowa USA
    Posts
    259

    Default Clarify Bore condition, Dark, Frosty,etc

    Here is a question that can be answered if anybody out there has a bore camera and pix, I had somebody ask me for explination on a bore I was describing.
    Can anybody explain bore conditions for us hopefully with pix?
    Bright, Dark, Frosty, Shiny, Pitted etc. and how these get into these conditions.
    It seems simple to us that have been around the bolt for awhile,
    I have a few people (guests) waiting to hopefully get some pix of
    these conditions, to help put 2 and 2 together for them.
    thanks..
    Orion

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  2. #2
    Join Date
    Dec 1969
    Location
    California
    Posts
    592

    Default

    It's funny, I had no idea what "frosty" looked like for the longest time... until I saw it for myself. Happened to one of my rifles I haden't used in a long time and forgot to clean after shooting (noncorrosive though!). Fortunately that 'frost' disappeared with a couple of patches...

    Sorry no pics though.

    -Palimino
    "The bullet is no respecter of fine uniforms." -Russian Proverb

  3. #3
    Join Date
    Dec 1969
    Posts
    1,482

    Default

    Quote Originally Posted by Orion61 View Post
    Here is a question that can be answered if anybody out there has a bore camera and pix, I had somebody ask me for explination on a bore I was describing.
    Can anybody explain bore conditions for us hopefully with pix?
    [B]Bright, Dark, Frosty, Shiny, Pitted
    Somewhat subjective, but this is how I interpret those terms:
    Bright= "very good" to "excellent", little or no pitting. Sharp and distinct lands and grooves, mirror-like in appearance.
    Shiney= "good" to "very good", similar to "Bright" but maybe with some very light pitting. A bore can have rounded lands and still be "shiney".
    Frosty= "fair". The "frost" is caused by millions of tiny pits on the surface of the bore. Frosty bores look "fuzzy".
    Dark="poor". Possibly rusted and/or deeply pitted. "Dark" is the classic importer/shady dealer way to avoid saying "poor condition".
    Sometimes a rifle is described as "dark with clear rifling" or some such; to me that says "poor to fair" overall.
    Last edited by FGD135; 03-19-2009 at 08:13 PM.
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  4. #4
    Join Date
    Dec 1969
    Location
    Central Finland
    Posts
    2,831

    Default

    I agree, this is very subjective topic.
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  5. #5
    Join Date
    Dec 1969
    Location
    Eastern Nebraska
    Posts
    1,018

    Default

    CH, I like those pictures. Should make a collage out of it for wallpaper on the computer.

  6. #6
    Join Date
    Feb 2009
    Posts
    543

    Default

    Antti, those pictures look great! Very professional.

    Is that something I could try with my regular cameras or do you have specialized equipment?

  7. #7
    Join Date
    Oct 2008
    Posts
    3,665

    Default

    Perhaps a little OT, but nonetheless related. I picked up a 44 SAKO M39 I had on layaway at a nearby gun store. (No more "sight unseen" gun purchases for me.) It has an arsenal tag, which I have deciphered using Doug Bowser's Rifles of The White Death.

    The tag has "7.59-7.65" rubber stamped in the caliber space. I presume this means that the rifle the tag was attached to has a bore within the range so marked, rather than having a taper.

    The 44 SAKO has a Westinghouse receiver, wartime stock, and the sweetest trigger I've encountered yet: light and crisp, with absolutely no creep. The "Syopaste" value is "1". Doug's book says this is a "corrosion" value, although I'm wondering if "erosion" might be a better translation.

  8. #8
    Join Date
    Oct 2008
    Posts
    3,665

    Default M39 Arsenal Tag

    Perhaps a little OT, but nonetheless related. I picked up a 44 SAKO M39 I had on layaway at a nearby gun store. (No more "sight unseen" gun purchases for me.) It has an arsenal tag, which I have deciphered using Doug Bowser's Rifles of The White Death.

    The tag has "7.59-7.65" rubber stamped in the caliber space. I presume this means that the rifle the tag was attached to has a bore within the range so marked, rather than having a taper.

    The 44 SAKO has a Westinghouse receiver, wartime stock, and the sweetest trigger I've encountered yet: light and crisp, with absolutely no creep. The "Syopaste" value is "1". Doug's book says this is a "corrosion" value, although I'm wondering if "erosion" might be a better translation.

  9. #9
    Join Date
    Dec 1969
    Posts
    513

    Default

    Beautiful photos!

    Tim

  10. #10
    Join Date
    Oct 2008
    Posts
    3,665

    Default

    For any particular projectile shape, mass, and CG there is an optimal velocity and rate of spin.
    A well worn barrel will engrave the projectile less, and thus have less friction, allowing the projectile to travel through the bore faster and exit the muzzle ahead of the gas jet enough to avoid being upset by the muzzle blast. This is known as "interior ballistics."

    Once the projectile leaves the muzzle, "exterior ballistics" govern the trajectory. This is where velocity, wind, gyroscopic precession (caused by the projectile's spin), drift (another effect caused by spin), air density, cavitation (the vacuum formed behind the projectile) and wobble (the combined effects of spin and the projectile's CG) affect trajectory.

    So, there is a lot going on between the time the primer ignites the propellant and the bullet's striking the target. Bore condition is only one factor.

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