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Thread: Will an undersized, out of round bullet bump up?

  1. #1
    Boolit Master Bazoo's Avatar
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    Will an undersized, out of round bullet bump up?

    So this question is general but applies to my mould. So I have an RCBS 44-245-SWC that I've been lapping intermittently as I get gumption. It casts with my ww alloy .429 across one section. Move a bullet 1/8 either way and it measures .430 and then larger across another portion.

    So let's say I need .430 for no leading and good accuracy. Not counting obturation, will that small section that's .429 bump up when the bullet goes into the rifling? If that spot hit right on a land I'd say it would be fine, what if it hit on a groove?

    This is something I've been pondering a while. I'm going to continue lapping my mould until it throws larger by the way.

    Opinions please.

    Thanks.

    Bazoo

  2. #2
    Boolit Master
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    Ive usually had bumping up in conjuntion with gas cutting and leading. For me dont seem like it happens fast enough to fix the issue

  3. #3
    Boolit Master
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    We really can't discount obturation Bazoo, it happens.

    When big, heavy bullets like your's are seated over near max charges they WILL obturate and do so quite well. And when a bullet enters the barrel the bullet will be exactly what the barrel is. That being true, I wouldn't (I don't) worry about a mystical thou.

    Now, if you were shooting hard alloy, light bullets over a modest charge the obturation effect could be small or non-existent and you might very well see a difference in performance.
    Last edited by 1hole; 03-22-2020 at 11:00 AM.

  4. #4
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    IMHO you can only judge how well the bullet shoots and whether it leads, with your alloy, lube, load and barrel. How does the bullet look and measure after being sized .430?
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  5. #5
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    Stop keeping us in suspense. Shoot it and see......
    " If you cant do it with a 308 , you dont need to do it!

  6. #6
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    CHOOT ! Liz-Beth CHOOT !
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  7. #7
    Stop there, cast a few dozen & test it. You can't polish the metal back on that mold. uncle mike

  8. #8
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    Sure it will. Depending on the alloy it may need to be pushed harder that beginning loads. It may leave deposits before obduration happens. It may never get balanced enough for great accuracy but it just might work well enough.
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  9. #9
    Boolit Master Bazoo's Avatar
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    Interesting responses, thanks. I haven't tried any of them yet since receiving my gun back from the factory. I had discounted the idea of trying them because the mould did drop .428 or a touch less on that section. I will see about loading some and report back as to how they do. Course it's possible my gun will still lead regardless.

    I will shoot some full house loads but mostly it'll be specials and starting magnums. My research suggests ww alloy won't obturate at those pressures. I don't have a supply of pure to mix with it for softer alloy.

    The reason I suggest to discount obturation is for purely theoretical reasons. I spend more time pondering guns, ballistics, and reloading than I do anything else.

  10. #10
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    JonB_in_Glencoe's Avatar
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    you don't say what the gun is?
    If it's a revolver? which I assume it is with the boolit mentioned, then the question is, what do the cylinder throats measure?
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  11. #11
    Boolit Master
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    Quote Originally Posted by Bazoo View Post
    I spend more time pondering guns, ballistics, and reloading than I do anything else.
    I spent lots of time trying different alloys and powders, diameter ect. for my 44 revolver, then once I had it good I never shot it again lol. the fun part was trying stuff then I go try something else with a different gun.

  12. #12
    Boolit Buddy
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    by the way, RCBS replaced one of my molds, several years ago, that I had a problem with....always an option if it is out of round, too small dia. etc.
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  13. #13
    Boolit Master Bazoo's Avatar
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    Quote Originally Posted by JonB_in_Glencoe View Post
    you don't say what the gun is?
    If it's a revolver? which I assume it is with the boolit mentioned, then the question is, what do the cylinder throats measure?
    It's a Ruger super blackhawk. I measured my throats at .432/.4325 with calipers and slugged bullets. The issue I had with the gun previously was leading. I returned it to Ruger and it came back with a new barrel and cylinder. I had used other moulds that throw fat with my testing previously, but have gotten rid of them.

  14. #14
    Boolit Master Bazoo's Avatar
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    Quote Originally Posted by AZ Pete View Post
    by the way, RCBS replaced one of my molds, several years ago, that I had a problem with....always an option if it is out of round, too small dia. etc.
    I've considered sending the mould back. I contacted RCBS via email and asked them about it. Their response was that they wouldn't replace it if I was the original owner. Which I'm not. They said they wouldn't lap it out, just replace it.

  15. #15
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    Quote Originally Posted by Bazoo View Post
    ...will that small section that's .429 bump up when the bullet goes into the rifling? If that spot hit right on a land I'd say it would be fine, what if it hit on a groove?

    This is something I've been pondering a while. I'm going to continue lapping my mould until it throws larger by the way.
    I think it will bump up fine, but obviously you'll have to shoot it to see for sure. I've had decent luck either lapping or Beagling molds that didn't spec out right.
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  16. #16
    Boolit Master Bazoo's Avatar
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    Rugerfan, thanks for addressing my query.

  17. #17
    Boolit Master Wheelguns 1961's Avatar
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    The problem that I have had, especially with softer alloys, is if your bullets don’t have a tight fit in your cylinder throats, you will get some blow bye, and the lead will deposit on your forcing cone, and sometimes the first couple inches of the barrel. A bullet with any amount of leading will not be as accurate as it could be.
    Due to the price of primers, warning shots will no longer be given!

  18. #18
    Boolit Master
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    Quote Originally Posted by skeettx View Post
    CHOOT ! Liz-Beth CHOOT !
    Oh dear, Skettx has been watching Swamp People again!

    Bazoo, If your alloy is relatively soft it should work out OK, something like 16:1 maybe.
    "We take a thousand moments for granted thinking there will be a thousand more to come. Each day, each breath, each beat of your heart is a gift. Live with love & joy, tomorrow is not promised to anyone......"

    unknown

  19. #19
    Boolit Master Bazoo's Avatar
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    My alloy is wheel weights with minimum tin. I do have about 30 pounds of sows and pure I've been hoarding but that won't go very far to alloy.

  20. #20
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    JonB_in_Glencoe's Avatar
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    Quote Originally Posted by Bazoo View Post
    It's a Ruger super blackhawk. I measured my throats at .432/.4325 with calipers and slugged bullets. The issue I had with the gun previously was leading. I returned it to Ruger and it came back with a new barrel and cylinder. I had used other moulds that throw fat with my testing previously, but have gotten rid of them.
    I assume you are saying your current throats are 4325
    If so, you should load boolits that are 4325 or a hair larger, for the sake of accuracy. Lead fouling may or may not occur with boolits smaller than the Throats, but still larger than barrel groove dia. I don't think COWW will bump up enough for you, Keep lapping my mold.
    ~~~~~~~~~~~~~~
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