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Thread: FYI This is how I do a pound cast.

  1. #101
    Boolit Master

    alamogunr's Avatar
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    I use a 3 lb drilling hammer. https://www.google.com/webhp?rls=ig#...rilling+hammer

    Just enough oil(or grease) to coat the surface. You don't want dry, bare steel.

    If I hunted I would definitely be envious.
    John
    W.TN

  2. #102
    Boolit Buddy don45's Avatar
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    Question

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    So far I've chickened out on doing the actual pound cast. Just very worried about getting this massive chunk of lead stuck or somehow damaging the bore. From other posts, I can't remember where, I sort of know what a Winchester M70 458 throat looks like so I decided to do an expirment using my set of pin gauges. I made a very shortened Hornady case gauge by drilling and tapping a .458 case and then shortened it so that the long pins will measure the chamber down to 2.5 inches, the length of a 458 case (photo 1). I did measurements in 1/1000 increments (incr. of pins) and recorded the length from case head to end of pin. I started at .451 (.450 slides freely through bore) and measured up to .488, then plotted the results (photo 3). I simplified the plot as photo 2.
    It seems to me that these results should be almost equivalent to measurements from an actual bore-cast. It also seems to me that there is no good way to fit a 350 gr bullet to this throat. The driving bands on most .458 boolits (ranch-dog, noe, lyman) is .460 which occurs at 3.0 inch from case base, i.e. 0.5 inch into throat. The short 350 gr NOE (460 350 RF2) would have to jump almost 1/2 inch before contact.
    Does anyone think this data is useful to bullet selection? If I go for an Accurate custom (e.g. 46-360J) what sizes should I specify? Would I have learned anything more / different from an actual pound-cast?
    Thanks,
    Don
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    ​Don
    NRA
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  3. #103
    Ok guys sorry but I am totally lost as to what is being shown to me.

  4. #104
    Boolit Master

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    OK I did my 1st pound cast today, I did this on my new Savage 111 Trophy Hunter 338 Win Mag.

    Question for those who Know what they are doing:

    - are most throats tapered? I measured the cast, the largest diameter was .348 and it tapered down to .338 ( I measured this with a pair of Brown & Sharpe calipers) I'm going to take the cat to work and measure it with both Micrometers & the comparator.
    - I'm guessing the "rough" ring of lead that formed at the end of the casing and before the throat shows the total depth of the chamber? This ring measured .065" in length.

    Thanks
    I'm looking for Lyman Truline Jr / 310 dies. PM me if you have any.

    Scott

    You can easily judge the character of others by how they treat those who they think can do nothing for them.

    38 Super - DOB 02/06
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    Delta Elite - DOB - 1989

  5. #105
    Boolit Master

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    First of all, when punching the cast out of the barrel, it is very common to actually bump the unsupported portion up a little the first time giving you a false reading in the throat area.
    To combat this, I usually file off the rifling marks, reinsert the chamber slug as is, and bump it again. Usually, the third time is a charm.

    Secondly: Yes, the throat is supposed to be tapered. Sometimes there is a parallel cylindrical section of 1/8" or so commonly referred to as "freebore" that connects the end of the chamber to the tapered throat, but this is often not beneficial to the cast bullet shooter (cast bullets are inherently shorter than jacketed grain for grain by weight, thus, no freebore is generally wanted or desired).
    When choosing a bullet design for your rifle, you do not want to go at all larger than the very largest reading just past the chamber where the taper begins. This is often .002 larger than the groove diameter of the rifle, and while I would use every bit of it, I would highly discourage the use of any bullet that is larger than the diameter of your throat entrance. That said, I would not go any larger than .002 over groove diameter. There is a list of priorities to fitting bullet diameter to the rifle for accurate shooting.

    Thirdly, rifle chambers are often longer than your brass by a good margin, just as you observe in your chamber cast there. This is not a problem for jacketed shooters, but doesn't do cast bullet shooters any favors whatsoever, especially if you are paper patching (you will get paper rings in your chamber that bear a striking resemblance to the depth and length of that gap, and you'll have to fish them out after each firing).

    All in all, looks like a good chamber slug. I would file off the riflings and do it again, just to verify what you are seeing is the real McCoy, but I don't see anything out of the ordinary right off the bat.
    Last edited by goodsteel; 03-15-2015 at 11:22 PM.
    Tim Malcolm
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    "He who is enslaved by the compass has freedom of the seas"

  6. #106
    Boolit Master

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    goodsteel that is good info as I always thought one and done but you make sense with doing it three times. Thanks for the explanation.
    Lead bullets Matter

    There are three kinds of men: The ones that learn by reading. The few who learn by observation. The rest of them have to pee on the electric fence and find out for themselves. - Will Rodgers

  7. #107
    Boolit Master

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    What we are after here is an accurate measurement of the chamber of your rifle. It stands to reason that if it really is "accurate" that it will also be repeatable and consistent.
    Try making three slugs of the same rifle and see if they agree. Try bumping one slug three times and see if it's always the same.
    I am confident that you will find, as I have, that bumping he slug two or three times is the most accurate, repeatable, and consistent way. It just gets closer to perfect each time.

    The reason for this is that when bumping the slug, obturation happens where the contact rod meats the pure lead, and radiates downward from there. This is the reason for using light taps with a large hammer. The object is to throw the energy as deep into the slug as possible so that you get the slug to open all the way down on the shoulder, and not just in the throat/neck area.
    Obviously, if you remove the area that you bumped up the most the first time without touching the area below it, the next time you bump it, you're going to get the area below the immediately effected area to bump a little closer to true size etc etc.

    Of course, there is a point of diminishing returns as the slug meets the wall of the chamber and can go no further.
    I have experimented with as many as 5 bumps, and have found that when using a large hammer, three cycles is enough to bump the slug to its maximum size all the way to the shoulder. Accurate and repeatable measurements can be taken from a slug formed in thus way.
    Tim Malcolm
    MBT custom rifles & gunsmithing
    www.goodsteelforum.com

    "He who is enslaved by the compass has freedom of the seas"

  8. #108
    Boolit Master Cowboy_Dan's Avatar
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    Has anyone done this with a steel case? Will it work? Rifle is a Mosin, case is copper-washed surplus.

  9. #109
    Boolit Master

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    Quote Originally Posted by Cowboy_Dan View Post
    Has anyone done this with a steel case? Will it work? Rifle is a Mosin, case is copper-washed surplus.
    A steel case will work just fine. Grind the casemouth back a little so that you can get a good rendering of the chamber neck area, but other than that, you're golden.
    Tim Malcolm
    MBT custom rifles & gunsmithing
    www.goodsteelforum.com

    "He who is enslaved by the compass has freedom of the seas"

  10. #110
    great info

  11. #111
    Boolit Man
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    Dumb question. Can you do a pound cast in a semi-auto rifle? I have a Remington 740 Woodsmaster in .30-06. Planning on beginning my hand at casting for that rifle before I dive into my new 7mm Rem Mag.

  12. #112
    Boolit Mold
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    Just wanted to say thank you for the info. Whilst I have hand loaded for years in 308 I have just started to down load and use cast . I am saving this page as I have learnt a great deal.

  13. #113
    Boolit Bub pcmacd's Avatar
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    Why not a cerosafe or Rotometals chamber alloy cast?

  14. #114
    Boolit Master


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    learn something new everyday , thanks for the info
    I like 1911's and Wheel Guns , Wood Stocks and Blue Metal , Dislike Black on Black and Magazines on Rifles whats this country coming to.
    Amateur Radio Station -KB5SMG- since 1994 Call sign change as of 8-15-17 WB5MG

  15. #115
    Boolit Master

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    Quote Originally Posted by pcmacd View Post
    Why not a cerosafe or Rotometals chamber alloy cast?
    The reason is that a cerosafe casting is not precise enough. Cerosafe grows and shrinks a lot, and is only good for +-.002 inches. It's simply not accurate enough, nor predictable. A pound cast never changes (at least not enough to matter) and when done correctly, is good for .0002 precision.
    Tim Malcolm
    MBT custom rifles & gunsmithing
    www.goodsteelforum.com

    "He who is enslaved by the compass has freedom of the seas"

  16. #116
    Boolit Master

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    Nice to hear from you goodsteal .

  17. #117
    Boolit Master

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    Years ago my old gunsmith friend (R.I.P.) put me on to sulpher/grafite for chamber casts. Works great as long as you do not ignite the sulphur
    It ain't rocket science, it's boolit science.

  18. #118
    Boolit Master



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    Just want to add another reason to do a pound cast over cerrosafe casting; if you have an old military rifle that has a pitted chamber I suspect the cerrosafe could lock in those pits and you'll wind up melting it to get it out!
    Dan in FL - Call me TD Savage 219 & 220 rifle/shotguns wanted.

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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