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Thread: Lead and copper fouling in barrel

  1. #21
    Boolit Master
    lwknight's Avatar
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    Thank you Mister 303Guy. That helps substantiate what I thought I knew all along. I never examined recovered rifle bullets but I have a few thousands of pistol bullets from a sand berm. I never did see any signs of erosion on any bases but them again I did not specifically have that idea in mind either. All my thoughts were on the rifling grooves and mushroom performance.
    Now I will pay special attention to any recovered paper patches to see if there is any sign of being burned other than smoke damage,
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  2. #22
    Boolit Grand Master 303Guy's Avatar
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    You're welcome. I found a clearer picture of the boolit base with patch ring indent plus gas cutting.



    I found this photo as well - now that's bad gas cutting!



    Here is a card wad still attached to the boolit showing no heat effects.



    I would not expect the paper that was cut away to be burned actually. The rings never show any sign of heat, nor do the patch fragments I recover.

    Last edited by 303Guy; 02-07-2018 at 02:08 AM.
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  3. #23
    Boolit Grand Master tazman's Avatar
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    Consider what happens with black powder shooting. In particular a patched round ball.
    You can find unburned patches in front of the firing line. Most show no damage but they have been lubed. An unlubed patch can often have a charred center where the burning powder actually set the patch on fire.
    With black powder pistols, you never hear much about leading in the barrels. I wonder if this is due to the usually heavy and large amounts of lube used to seal the chambers.

  4. #24
    Boolit Master buckshotshoey's Avatar
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    I was working up a load for my 45-70 and using Varget and wheel weights. Near the top end, I was seeing perfect impressions of the Varget grains into the base. Don't know if they were being burned in, or just pressed in. I'm looking for the photo. Think I re-melted the recovered boolits.

  5. #25
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    The grain impressions are being pressed or hammered into the bullet base. The fire starts at the back of the case and pushes everything forward so you are seeing the impression of powder grains that have not yet been consumed.

  6. #26
    Boolit Master buckshotshoey's Avatar
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    Quote Originally Posted by Dusty Bannister View Post
    The grain impressions are being pressed or hammered into the bullet base. The fire starts at the back of the case and pushes everything forward so you are seeing the impression of powder grains that have not yet been consumed.
    However it did it, it was pretty cool.

  7. #27
    Boolit Grand Master 303Guy's Avatar
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    I have a photo of kernel impressions in the boolit base. I set powder kernels into the impressions for a photo.



    I haven't been able to find the pic without the kernels.

    Found this one - different boolit.



    The one on the left had filler which protected the base.
    Last edited by 303Guy; 02-08-2018 at 03:46 AM.
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  8. #28
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    Quote Originally Posted by buckshotshoey View Post
    Is the major source of lead/copper fouling in a barrel due to friction? Or is it due to the hot powder gasses vaporizing the metal and depositing down the barrel?
    There are different kinds of leading and different mechanisms. For example flame cutting early in the barrel, versus friction transfer after lubrication failure near the end of the barrel, when propellant gas temperatures are low and pressure is moderate, but boolit velocity is high.
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  9. #29
    Boolit Grand Master 303Guy's Avatar
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    Quote Originally Posted by HangFireW8 View Post
    There are different kinds of leading and different mechanisms. For example flame cutting early in the barrel, versus friction transfer after lubrication failure near the end of the barrel, when propellant gas temperatures are low and pressure is moderate, but boolit velocity is high.
    I was thinking about this. I have found evidence of both mechanisms. Gas erosion causes grainy deposits while friction leading leaves long streaks of lead. I would think the grainy deposits could get smeared and fused into longer strips by subsequent shots.
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  10. #30
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    Quote Originally Posted by buckshotshoey View Post
    Is the major source of lead/copper fouling in a barrel due to friction? Or is it due to the hot powder gasses vaporizing the metal and depositing down the barrel?

    My opinion is vaporization. Hodgdon CFE powder works (I think) by chemically not allowing the vaporized copper to stick to the barrel.

    Discussion?........
    Another angle to think about is the heat transfer from the hot gasses to the bullet. If the heat transfer rate is not high enough the surface ( may just be one molecule thick melts and carried away with the gas flow) will be vaporized. This is the way some of the solid fuel rocket nozzels work. France had some of the original patents. To work you had to use material that had a relatively low heat transfer coefficient and the higher melting temperature the better.

  11. #31
    Boolit Master buckshotshoey's Avatar
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    Quote Originally Posted by 303Guy View Post
    I was thinking about this. I have found evidence of both mechanisms. Gas erosion causes grainy deposits while friction leading leaves long streaks of lead. I would think the grainy deposits could get smeared and fused into longer strips by subsequent shots.
    I don't think I have ever had a barrel that shaved off long streaks. I would assume that barrel has serious problems. As it is being described, I envision a rough spot in the barrel, and it is rubbing off lead in one spot. Not all the way around the circumference. I have never had a barrel do this that I can recall. Of course I don't have a borescope either. Maybe it's time to invest in one.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check