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Thread: How much does pc add to bullet diameter?

  1. #1
    Boolit Buddy Wheelguns 1961's Avatar
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    How much does pc add to bullet diameter?

    I want to start casting and powder coating .32 cal bullets. I have a single seven that I shoot .313 bullets in. I have a single six .32HRM that likes .314 bullets. I have molds on the way that are supposed to drop at .314. Do I size a bullet at .312 then p.c. And resize to .313? Likewise, for .314 bullets, do I size .313, then powder coat and size again at .314? How much does the powder coat add to the diameter? I hope I have explained this ok. Thanks in advance for any insight you pros may be able to give me.

  2. #2
    Boolit Master
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    The thickness of the coating can vary due to the powder used or the process, but generally a single coat is about 1.5-2 mils in thickness from the substrate. For rifles I try for approximately 3 mils, similar to a jacket thickness.
    I would suggest PC your bullets as they come out of the mold, then size to whatever works best in the particular gun.

  3. #3
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    Quote Originally Posted by Dragonheart View Post
    The thickness of the coating can vary due to the powder used or the process, but generally a single coat is about 1.5-2 mils in thickness from the substrate. For rifles I try for approximately 3 mils, similar to a jacket thickness.
    I would suggest PC your bullets as they come out of the mold, then size to whatever works best in the particular gun.
    Does this mean that the diameter of the boolit is increased 3-4 mils? IOW, if I want a .313 boolit from a mold that drops .314, I would powder coat it to .317 and then size it to .313?
    John
    W.TN

  4. #4
    Boolit Master

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    Depends some on the powder, finer powder will yield a thinner coat. I use smokes clear the most and a thin (blow off the extra) coat will add 1-2 thousandth to the total diameter. A heavy, fuzzy coat of some coarser powder by the pound stuff I started with adds 3+ total. Also, I always size after coating, even when I am intentionally adding 3-4 thousandth to increase size. Never had a problem with coating coming off.
    "In God we trust, in all others, check the manual!"

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    I cast some 356402 they drop 0.356. 1 coat Smokes flame red they miced .3585 I'll resize to .357 for use in my 9 mm's.
    Steve,

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  6. #6
    Boolit Buddy
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    Usually increases dia. By .001, you will need to check after power coating, then resize as necessary, or just resize it down the Bbl. If it chambers.

  7. #7
    Boolit Buddy Wheelguns 1961's Avatar
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    Quote Originally Posted by jcren View Post
    Depends some on the powder, finer powder will yield a thinner coat. I use smokes clear the most and a thin (blow off the extra) coat will add 1-2 thousandth to the total diameter. A heavy, fuzzy coat of some coarser powder by the pound stuff I started with adds 3+ total. Also, I always size after coating, even when I am intentionally adding 3-4 thousandth to increase size. Never had a problem with coating coming off.
    So it sounds like I could size all to .312 out of the mold, then powdercoat all. Then just final size to .313 or .314 depending on which gun I need them for. Does this sound good?

  8. #8
    Boolit Master
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    If you tumble coat and how you tumble coat typically you will end up with a thicker coating than spraying. The type and brand of powder and the color can alter the thickness of the polymer.
    If you are first starting out then you will probably be tumble coating. I would suggest getting you powder from Smoke at least to start with as his powder is a proven performer. Follow the standard procedure for PC and then size as you normally would. You should have no trouble doing what you you have outlined. A +.003 increase or less in the diameter due to PC should pose no problems going through your sizer.
    If you have any problems or questions, just ask.

  9. #9
    Boolit Buddy Wheelguns 1961's Avatar
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    You have all cleared up some of my questions. Thank you to all. Keep it coming. I really appreciate it. This forum sure is great!

  10. #10
    Boolit Master

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    The PC usually makes them so slick that you'd have to have a mic to tell the sizer was doing anything. Even going down .004 or .005, it might feel like it isn't even sizing them any. Sometimes I have to double check and make sure I grabbed the right sizer die. If it's done right, they get pretty slippery!
    KE4GWE - - - - - - Colt 1860, it just feels right.

  11. #11
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    PC generally adds ~0.001 thickness(on each side) x2 = 0.002 total increase. That thickness will depend on whether you ASBBT correctly (!) or use ESPC. And how you hold your mouth! ASBBT has the largest variations I have seen over the past 4+ years.

    Bottom line.........go ahead and PC your boolits and size to what your barrel asks for. It just works!

    Don’t get lost in the weeds of worrying about 0.0005 thickness variations. Your sizing die will get you back to what your gun barrel wants.

    Happy coating!

    Bangerjim

  12. #12
    Boolit Master Grmps's Avatar
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    As previously said, different Powders will add different thicknesses. If you ASDT, make sure you knock off ALL the excess powder before baking.
    You can ask smoke what powders he has go on thinnest to thickest.

    I always size after PC, sizing down 3-4 thou isn't a problem. The harder the alloy, the lighter the boolit and the harder to size down. a little lanolin/alcohol case lube can help with sizing

  13. #13
    Boolit Master
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    I think that perhaps the BIGGEST consideration has not been discussed. From what I have read,
    one of the problems powder coaters have encountered is scraping off the powder coat when sizing down.
    It depends on your sizing die as to whether you can size down a .318" powder coated boolet to .314". If the sizing die has a tapered lead in, It will not scrape the powder off. But if the boolit encounters a sharp edge while entering the die it will scrape. I think if you have them scrape you could carefully polish the opening of the die a little so they would enter the die without hitting the edge. Now ...I have never run into this problem personally. So I could be wrong here. I trust that others will correct me if so.
    AKA hans.pcguy

  14. #14
    Boolit Buddy Wheelguns 1961's Avatar
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    Quote Originally Posted by Traffer View Post
    I think that perhaps the BIGGEST consideration has not been discussed. From what I have read,
    one of the problems powder coaters have encountered is scraping off the powder coat when sizing down.
    It depends on your sizing die as to whether you can size down a .318" powder coated boolet to .314". If the sizing die has a tapered lead in, It will not scrape the powder off. But if the boolit encounters a sharp edge while entering the die it will scrape. I think if you have them scrape you could carefully polish the opening of the die a little so they would enter the die without hitting the edge. Now ...I have never run into this problem personally. So I could be wrong here. I trust that others will correct me if so.
    What brand sizing dies do you reccomend?

  15. #15
    Boolit Master
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    Quote Originally Posted by Traffer View Post
    I think that perhaps the BIGGEST consideration has not been discussed. From what I have read,
    one of the problems powder coaters have encountered is scraping off the powder coat when sizing down.
    It depends on your sizing die as to whether you can size down a .318" powder coated boolet to .314". If the sizing die has a tapered lead in, It will not scrape the powder off. But if the boolit encounters a sharp edge while entering the die it will scrape. I think if you have them scrape you could carefully polish the opening of the die a little so they would enter the die without hitting the edge. Now ...I have never run into this problem personally. So I could be wrong here. I trust that others will correct me if so.
    Scraping off the PC is NOT a problem for 95% of coaters. It will NOT come off as long as you have coated properly, cured properly, your dies are not rough and torn up inside, and you are not trying to size from 45 cal down to 30 cal!!!!!!!

    In the many MANY thousands of boolits I have coated and sized, not a one has ever lost the coating in the smooth sizing dies. And you do NOT need any lube in there! That just creates another step or two cleaning off the stupid soap or whatever you use.

    CURED PC is very resilient and very slick and will easily pass thru good CLEAN (no gauled Pb) quality sizing dies with no problem. I use Lee dies exclusively with ZERO problem.

    Scraping off of PC in a die is one of the LEAST things I worry about when coating, loading, and shooting! I have been doing PC for 4+ years now and have a ton of experience with all the do’s and don’t about it, as many others on here do also.

    Bangerjim

  16. #16
    Boolit Master Grmps's Avatar
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    If PC or HiTek scrape off in a sizing die the die needs to be polished to remove any roughness that shouldn't be there. I've sized PC on a lube-sizer, Lee and NOE sizing dies, I had to polish 2 dies that were rough now all work flawlessly.

  17. #17
    Boolit Buddy Wheelguns 1961's Avatar
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    That all makes sense. Thanks again everybody!

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