close

Privacy guaranteed - Your email is not shared with anyone.

Welcome to Glock Talk

Why should YOU join our Glock forum?

  • Converse with other Glock Enthusiasts
  • Learn about the latest hunting products
  • Becoming a member is FREE and EASY

If you consider yourself a beginner or an avid shooter, the Glock Talk community is your place to discuss self defense, concealed carry, reloading, target shooting, and all things Glock.

Voids inside Bullets.

Discussion in 'Reloading' started by Colorado4Wheel, Aug 21, 2011.

  1. Colorado4Wheel

    Colorado4Wheel

    14,938
    170
    Nov 2, 2006
    CO
    I have started to have problems with my bullets “keyholing”. I thought some were slightly undersized because they sized easily. So I was drilling some holes through the base of the bullets to try and make the molds a little bigger when I noticed that I was hitting some voids. At least that’s how it felt. So I filed a bullet in half and sure enough, small void near the middle. When I cast I seem to need to be at 800F to get good fill out on my Lyman 4 cavity 147gr 9mm molds. I cast using two at the same time. I think it may because I sometimes get a pretty slow pour from my Lee pot near the end. Sometimes I forget to open the adjuster on the valve a little more as the pot goes down as well. Both result in the occasional slow fill of the mold. Besides that these bullets look good. Any other ideas? This new batch is range scrap. Not WW.
     
  2. freakshow10mm

    freakshow10mm 10mm Advocate

    I would add tin to help fill the mold out. I usually add just 2% (by weight) tin to range scrap, since it's more towards the pure lead spectrum. Doesn't add much hardness, but tin helps fill more consistently.

    800F seems high for this application. Unless I'm casting 20ga slugs or BP round balls, I keep it 650-675F.
     


  3. Three-Five-Seven

    Three-Five-Seven Señor Mombo Millennium Member

    2,727
    34
    Aug 8, 1999
    Great Southwest
    There should be a SUBSTANTIAL amount of sprue on top of the plate before you cut it. The sprue acts as a reservoir to deliver lead to the bullet as it cools. Additionally, if you're not getting frosted bullets, you're not at a high enough temperature. While frosting on bullets is not the goal, it is the only indicator of how hot the mold and lead is, and therefore how fast you should be working.

    I find range scrap to be hard, relative to the bullet I'm aiming for. A good supply of pure lead on hand is essential when working with range scrap in my experience. More tin and antimony requires more heat and they solidify differently than pure lead or a normal, 20/1 or 30/1 alloy. I have never found a reason to add antimony to lead for casting, but you can be sure range scrap has a substantial amount in it.

    So....

    1. Get a significant sprue on top of the plate before moving to the next hole.
    2. Raise your temp.
    3. "Soften" your alloy with pure lead. (I mix range and pure 50/50 when making regular bullets and don't use any range scrap at all when making precision bullets).
     
  4. WiskyT

    WiskyT Malcontent

    11,682
    1
    Jun 12, 2002
    North Carolina
    I don't know about voids. Tin like Freak said aids fillout so it certainly wouldn't hurt.

    I don't think voids are casuing your keyholing. RS is softer than WW. That will definately cause keyholing. Harden your bullets, lower your charge, or use a slower powder. Someday you'll try Unique and then your cast bullet loading will be much easier. When you do, I won't say "I told you so", but I'm sure Jack will.
     
  5. Colorado4Wheel

    Colorado4Wheel

    14,938
    170
    Nov 2, 2006
    CO
    I should add that the Keyholing is just about 1 in 25 bullets. Not every shot.

    I think the keyholing is due to some undersized bullets. I was just surprised to see a void.
     
    Last edited: Aug 21, 2011
  6. WiskyT

    WiskyT Malcontent

    11,682
    1
    Jun 12, 2002
    North Carolina
    A softer bullet will mic smaller than a harder bullet if you don't run the mic loose. If the edges of the lube band etc are sharp, they are probably big enough.

    Try a slower powder. I tell you that to save you grief.
     
  7. UNIQUE. It's not just for Great Grandad anymore.
     
    Last edited: Aug 21, 2011
  8. Colorado4Wheel

    Colorado4Wheel

    14,938
    170
    Nov 2, 2006
    CO
    Up until my last batch everything was fine. I think I was just getting good fill out in the mold. Unique isn't going to solve that is it?
     
  9. Zombie Steve

    Zombie Steve Decap Pin Killa

    18,083
    18
    May 31, 2007
    Old Colorado City
    Throw a big pile of Unique in the pot when you're fluxing. You don't need eyebrows, really.
     
  10. ron59

    ron59 Bustin Caps

    6,927
    20
    Jan 3, 2009
    Smyrna, GA
    You seem to be getting funnier and funnier.

    :rofl::rofl:
     
  11. You are on fire today Steve.
     
  12. GioaJack

    GioaJack Conifer Jack

    10,016
    1
    Apr 14, 2009
    Conifer, CO
    Voids are caused by several factors and each one has to be addressed individually. In no order of importance some of the reasons are;

    Allowing the alloy in the furnace to get too low which decreases the velocity of the pour. It's a pretty good idea to never let the level drop below a third full.

    Insufficient fluxing will allow your tin and antimony to float in suspension resulting in an abnormally high concentration of lead during the pour. The first indication of this is rounded edges on driving bands but can also result in voids.

    Cutting off pour before a sufficient sprue has formed but with good flow velocity heavy sprue is not as important.

    Tilting the mould during pour can easily result in voids and usually occurs as a result of fatigue.

    A loose sprue plate will allow base finning which results in voids.

    Knocking off the sprue before fully hardened will actually pull alloy out of the base of the bullet which leaves a void.

    Pouring directly down the middle of the sprue plate hole can cause an air void in the bullet. Pouring slightly off-center allows the alloy to swirl as it fills the mould and ensures that all air is forced out of the cavity.

    Clogged vent lines in the mould face can cause voids as well as finning. Clean mould face with 000 steel wool to keep lines clear.

    I really don't see why you need to pour at 800 degrees with an iron mould but if it works for you then I guess that's the way to do it. I never pour higher than 700 degrees. (Have no idea about aluminum moulds.)


    Jack
     
  13. freakshow10mm

    freakshow10mm 10mm Advocate

    Jack, aluminum conducts heat better than iron, so the heat transfer is more consistent with aluminum than iron.
     
  14. fredj338

    fredj338

    21,741
    941
    Dec 22, 2004
    so.cal.
    Jack has some good points, but holes in the base are not the same as internal voids. Sometimes it's just technique w/ that alloy/mold, sometimes it's just bad luck. The only way to find the bullets w/ a void is weigh them. None of my cast bullets, even the really big ones, vary more than 1%. So anything greater than that, probably has an internal void & goes back to the pot. The only ones I do this with are hunting bullets or bullets used for longer range work.
    Adding tin to any lesser alloy will help as the tin makes the alloy flow better. Range scrap can & is often anything. I find at my range, it's on the softer side, about what I get if I mix clip ww w/ pure lead & I treat it as such. So I tend to pressure cast, especially smaller bullets. It seems to help mold fill-out. I rarely get casting temps above 750deg w/ any alloy, even 25-1 lead/tin for LHP runs fine @ 750deg.
     
  15. Colorado4Wheel

    Colorado4Wheel

    14,938
    170
    Nov 2, 2006
    CO
    Jack,

    I am using steal Lyman Molds. I think its a combination of

    Letting the lead pour straight into mold. I used to let it hit the sprue plate a little. I was being lazy.
    Vent lines could be cleaned.
    Casting with molds too cold.

    First and last ones are the most important i think.
     
  16. Tpro

    Tpro On the mark

    188
    0
    May 12, 2011
    Right side of Washington
    This ^^COULD^^ help but if it was me, and I was looking for the full effect I would use Tite Group.

    That should get it done, including eyelashes:wavey:
     
  17. WiskyT

    WiskyT Malcontent

    11,682
    1
    Jun 12, 2002
    North Carolina
    Is Unique going to solve your barking up the wrong tree? No.
     
  18. fredj338

    fredj338

    21,741
    941
    Dec 22, 2004
    so.cal.
    FLux more often, try pressure casting. A small amount of tin wouldn't hurt, say 1/2%-1%.:dunno:
     
    Last edited: Aug 22, 2011
  19. Colorado4Wheel

    Colorado4Wheel

    14,938
    170
    Nov 2, 2006
    CO
    I have a temp gauge and I measured the temp of the mold. Basically, the mold was not getting hot enough because I am casting with two molds. I used a hot plate and cast faster. That seems to have solved the issue. Better fill out. Better sizing. More consistent weight. I still need to clean the vent lines but it's far better now.