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Thread: Curious thing!

  1. #1
    Boolit Master

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    Curious thing!

    I was shooting my 8mm Mauser yesterday using PC'ed boolits. Some of the loads were pretty hot and I was using 4895 powder. Now for the curious part. I got some leading....but not in the barrel! The barrel was clean for its entire length. The leading was on the outside on the barrel crown! There was a star of lead that flaked off using my fingernail. I've never seen that before. The boolit was a 150 gr. spire point plain base in front a max of 35 gr. of powder and it provided a healthy recoil. Anyone else ever see this?

  2. #2
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    swheeler's Avatar
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    Nope never seen that. I would think the entire barrel would be leaded stem to stern with some lead build up oozing out the muzzle like you describe. 35 gr 4895(any flavor) has to be pushing your plain based 150 gr bullet at y2k or better, should be plenty of gas cutting going on?
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  3. #3
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    Winger Ed.'s Avatar
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    I've seen what I thought was just lube on the crown.

    If the lands cut their grooves instead of smashing them into the boolit, and the little slivers rolled in behind the base,
    it might be from that. The star pattern might jive up with the rifiling lands or grooves.

    In slo-mo pictures of a boolit exiting, you can see a flash behind it that blows outward.
    As the gases escaped, some lead might have been deposited on the crown, either from melting the rear of the base,
    or vaporized stuff cut off from the rifling.
    Last edited by Winger Ed.; 06-04-2019 at 08:39 PM.
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  4. #4
    Boolit Master

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    Like I said, those loads were hot for cast. But the barrel is clean. The loads were fair as far as accuracy goes but 33.8 gr IMR 4895 was best with 2-Xs, 2-10s and 1-9 at 100 in about 1 1/2 inch group. That is certainly respectable and would stop a deer in its tracks. That was shot AFTER all of the higher loadings, working backwards from the top. After 100 rounds, the barrel is still spotless. Yes, the star matched the grooves. I was surprised that I didn't get leading at those speeds. Didn't chrono those loads, but I will next time out.

  5. #5
    DOR RED BEAR's Avatar
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    New one on me to ain't never seen that.

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    Is your alloy high with antimony? Seen that before. What condition is the bore? Rusty or pitted?

  7. #7
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    We know the bullet bases didn't get deformed, unevenly anyway as posted accuracy is excellent, quite surprising to me for Plain Based at that speed. With enough lead to be scraped off the muzzle with a fingernail I would think some would have to stick to inside of barrel. Were your bullets cast of Linotype, maybe antimony wash, grey powdery stain? With that kind of accuracy and speed I wouldn't care, just wipe off muzzle at the end of the day.
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  8. #8
    Boolit Grand Master popper's Avatar
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    I've seen that on my AR10 308W. My take, any hot lead 'dust' shot gets stuck in the flash hider. Stopped when I removed the flash hider. You're using PB so any gas cutting gets deposited when the boolit leaves the muzzle.
    Whatever!

  9. #9
    Boolit Master

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    Boolits were cast from 50/50 coww/lino. They were pretty hard. Even with PC I expected some leading, but don't see any sign of it, just the "star" on the crown. And no, it wasn't antimony wash. I know what that is and it wasn't that. It was shiny lead flakes. The bore in this M48 Yugo is in excellent condition. The worst group was the 35 grain load that spread out to around 5 inches. Not that bad when you consider that without the flyer, it would have been under 4. I don't know what possessed me to try pushing a plain base boolit that fast, but I'm not complaining about the results. I was surprised when they were all on the target!

  10. #10
    Boolit Master

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    Modern bullet theory on lubes seems to be that to a degree they prevent the alloy from soldering to the barrel. Perhaps PC is doing the same thing, there may be a small amount of metal removed from the bullet due to engraving the rifling...but the whole process works because none of it sticks to anything inside the bore.
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  11. #11
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    A couple of questions:
    What PC were you using and how long/hot did you bake them at?

  12. #12
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    is it possible the pc bullet were pushing some barrel leading that was already there out? If not the only way I can see it happening is the pc isn't holding up where it contacts the rifling. Ive had recovered pc bullets with the pc all stripped away and bare lead showing on the recovered bullet and shot as many as a 100 of them in my 300 bo at 2000 fps without leading. I guess I figured the gas check was helping push some of the lead left behind out and kept the barrel clean.

  13. #13
    Boolit Master

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    The PC I was using was from a commercial coater. Can't tell you the brand, but it was high quality. Baked it for 20 minute from the time it started to get shiny. Temp was 400°. I doubt that there was any residue lead in the barrel. I've only shot FMJ through it since I've had it and I recently scrubbed the heck out of it till all I got was clean patches. No gas checks on those boolits either. That is why this is such a mystery to me. I can think of no explanation for the lead star on the crown.

  14. #14
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    I can, the PC failed. It rubbed through somewhere.

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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