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Thread: Stupid question/observation? Rifle bore.

  1. #1
    Join Date
    Mar 2005
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    Default Stupid question/observation? Rifle bore.

    Ok, get the eye-rolling over with right up front.

    I'm not really a "gun person," although I like to shoot once in a while when I get a chance.

    Years ago, I had the experience of accidentally discharging a pistol. No injury to property or person resulted, mostly because the bullet stopped and stuck halfway down the barrel. (And yes, this resulted in a somewhat awkward conversation/admission to my father, the owner of said pistol.)

    Fast forward a bit. Using a tubing cutter, I managed to "disassemble" a rifle cartridge. Since I didn't care about "saving the brass," I figured this was a reasonably safe way to separate the powder from the bullet and render the cartridge pretty much inert. Basically, just gently cut the thing in half and dump out the powder.

    So now I have an unloaded rifle and just the bare bullet that's supposed to be fired from this rifle. But the bullet won't fit in the barrel. It's in the right neighborhood, but if I wanted to push this thing the length of the barrel, I'd have to use a hammer.

    Is this what should be expected, and if so, how much of an "interference fit" is there supposed to be? This would go a long way to explaining what happened with the pistol so many years ago. (Someone mentioned something about "old ammo," too.)

    Thanks in advance.

    -M

  2. #2
    Join Date
    Dec 2004
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    where the Snake swallows the Salmon
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    Default

    There is a lot of confusion about "bore diameter" vs. "groove diameter."

    In the old days of cut rifling, a barrel was rifled in two steps.

    First, the "bore" was drilled and reamed. For example, a 30 caliber bore is typically 0.300".

    Second, the rifling grooves were cut. Grooves are typically cut 0.004" deep. So you end up with several 0.004" deep grooves around this 0.300" bore. That results in 0.308" "groove diameter."

    So..... the typical 30 caliber barrel has a 0.300" bore and 0.308" groove diameter. It is loaded with a 0.308" bullet. When the gun is fired, the 0.308" bullet must be engraved by the "lands" before it can pass through the barrel. That's why you cannot push a bullet through a barrel with finger pressure.

    As for your accidental discharge that stuck in the barrel, that is usually caused by poor ignition. The primer has enough power to push the bullet a little ways, but if the powder fails to ignite properly, the bullet may not even exit the barrel. It used to be a common problem with the first generation of ball powders, and still is a problem with some military surplus ball powders.

  3. #3
    Join Date
    Mar 2005
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    Virginia, DC suburbs
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    Default

    Well thanks for that MTN.

    Interesting, too. "Poor ignition" you say? Wow. I'm certainly no expert, but I remember that, at the time, it sure didn't sound like poor ignition. I was so lucky.

    This all reminds me of how, at the extremes, things tend to get a little weird. (High speed, high current, high frequency, etc.)

  4. #4

    Default

    Every word MTN GUN said is very true!

    If you truly would like to check the bore you need a dead soft lead round ball maybe 2 thou over. .310 for a 308 size bore. Lube up the bore good.

    A brass rod is best in that it will not hurt the rifleing.
    The muzzle end of the barrel is the MOST touchy part so DON"T TOUCH IT!
    If you hurt the rifleing that gun will never shoot as well as before without it being recrouned.

    Even number land & groves can be measured directly, Odds need to be calculated.

    If you are trying to figure out the bore size from the cartridge name, forget it.
    Look around the reloading sights and find the Dia. of the bullet that is being loaded, that's your number.

    As a side bar.
    That gun w/ the stuck bullet could be caused by the cartridge being left in a gun that was well oiled. oil gets in the cartridge and making the powder inert.
    This can also happen with the primer then nothing happens.

    Cartridges left in a very hot place will cause the powder to change and not always for the better.

    If you would like to take other cartridges apart, soak it for weeks in kerosene, this will render the primer a powder inert

  5. #5
    Join Date
    Jan 2005
    Location
    Indianapolis, Fort Lauderdale, Babbit MN
    Posts
    595

    Default Bullet puller

    An "inertia" type bullet puller can be used to safely remove a bullet from a live round.
    I bought one at Gander Mountain for less than $20. It fits many sizes of cartridges.
    Bill
    I cut it off twice and it's still too short!

  6. #6
    Join Date
    Jan 2006
    Location
    Northern Neck Virginia
    Posts
    496

    Default

    Quote Originally Posted by Seastar
    An "inertia" type bullet puller can be used to safely remove a bullet from a live round.
    I bought one at Gander Mountain for less than $20. It fits many sizes of cartridges.
    Bill
    And if you do grow into being a "gun guy" and start reloading... you're gonna need a good bullet puller eventually anyway.
    Ignorance is curable through education.

  7. #7
    Join Date
    Mar 2005
    Location
    Virginia, DC suburbs
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    Default

    Quote Originally Posted by Seastar
    An "inertia" type bullet puller can be used to safely remove a bullet from a live round.
    I bought one at Gander Mountain for less than $20. It fits many sizes of cartridges.
    Bill
    Hey, Bill -
    I think I'd like to check that out. Do you know a "search-able" name for this "inertia-type" bullet puller? Thanks.

    -M

  8. #8

    Default

    E-Bay
    RCBS bullet puller

    It looks something like a hammer.

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