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cast bullets

Post by rebs on 7/30/2017, 1:56 pm

Are cast 158 gr lswc bullets with a BIN of 12 to 14 considered as soft as swagged bullets ? Should they shoot as good as swagged bullets ?

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Re: cast bullets

Post by james r chapman on 7/30/2017, 3:18 pm

No cast bullet is as soft as a swaged bullet.

Yes, a properly cast bullet will shoot as accurately.
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Re: cast bullets

Post by orpheoet on 7/30/2017, 4:01 pm

http://www.dardascastbullets.com/mm5/merchant.mvc?Screen=PROD&Store_Code=dardas&Product_Code=38158SWCBB1000&Category_Code=38
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Re: cast bullets

Post by NuJudge on 7/30/2017, 4:29 pm

With most cast metals, there is shrinkage on freezing.  If there is shrink on freezing, the freezing happens from the outside to the inside, and the liquid metal is an alloy, you will have some porosity to the solid metal after it freezes.  If the porosity voids are small and evenly distributed, they should not have significant effect on ballistics.  If there is a large void, eccentric to the centerline of the bullet, you have a worst case and a flier.  

A properly cast bullet will have liquid metal poured in, in such as way as to result in no large voids.  For my cast bullets, I try to do this by having the top of the mold be really hot and a lot of liquid metal to feed the freezing bullet.  Tin will help reduce porosity, as the Lead crystal Dendrites growing into the liquid are affected and less restrict Lead liquid flow to empty areas.

Cast Lead hardness depends on a bunch of things, including what the alloy composition is, how the bullet froze, if there has been cold work on the bullet after freezing, and whether the alloy experiences aging at room temperature.  If you add some Tin you get a little hardening once frozen, but it reduces the melting point a lot.  A little bit of Antimony will harden Lead a good bit, but if you add both Tin and Antimony you get far more hardening.  If you quench a Lead-Tin-Antimony bullet from the mold, you may get bullets so hard they ring when dropped on a floor.  The quench causes the Lead-Tin-Antimony precipitates to be really fine and evenly dispersed in the bullet, giving generally higher hardness.  If the cooling is slower, the precipitates coalesce into fewer, larger precipitates, giving a lesser hardness increase.  

Lead has in some ways a weird metallurgy, in that a sample can loose much of its hardness by cold working.  All the metals I am familiar with experience something called "Recrystallization."  Recrystallization is the spontaneous reorganization of the crystal lattice to eliminate distortions of the lattice, and these distortions of the lattice are one reason for a metal to resist deformation.  The energy of the distortions in the crystal lattice are what drive recrystallization.  For some reason, Recrystallization happens for all metals I am familiar with at a temperature which is about one half of the melting temperature in degrees absolute, Rankin or Kelvin.  For Lead, that is about room temperature.  What this means is if you cold work Lead at room temperature, you will probably lose the hardening effect of the cold work, plus most or all from alloying, heat treatment and other causes.  

Swaged Lead bullets are thought by many to be nearly pure Lead, but I believe most to be a relatively soft alloy.  There was a thread on one of the 1911 or Bullseye forums recently on their composition.

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Re: cast bullets

Post by jmdavis on 7/30/2017, 8:58 pm

I really like the Dardas .452 cast bullets. Quality control has been very good.
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Re: cast bullets

Post by noylj on 7/31/2017, 12:44 pm

10-13 BHN is hard enough for every handgun I have shot, up to and including hot .44 Rem Mag loads. The difference is that swaged bullets don't have air pockets in them from the casting process and are as consistent in weight and dimension as jacketed.
Everyone KNOWS swaged bullets are super soft. 
Here is what I have found:
I decided to contact the bullet companies I know that made swaged lead bullets.

Magnus uses 97/3 alloy for 650-800 fps. This alloy is BHN 11.
 
Precision Bullets uses 92/6/2 and reports the bore-riding surfaces are 13-14 BHN. They also restrike after the coating process.
 
Hornady reports 95/5, for 13 BHN.
 
Zero uses 97/3, also, for BHN of 11
 
Speer reports it is proprietary, and they “have a max velocity of 1100 fps.”

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Re: cast bullets

Post by USSR on 8/1/2017, 11:16 am

noylj wrote:Everyone KNOWS swaged bullets are super soft. 
Here is what I have found:
I decided to contact the bullet companies I know that made swaged lead bullets.

Magnus uses 97/3 alloy for 650-800 fps. This alloy is BHN 11.
 
Precision Bullets uses 92/6/2 and reports the bore-riding surfaces are 13-14 BHN. They also restrike after the coating process.
 
Hornady reports 95/5, for 13 BHN.
 
Zero uses 97/3, also, for BHN of 11”

Had to laugh.   You can call it soft, but when it has a BHN of 11 or more, IT AIN'T SOFT!   Elmer Keith's bullets for his .44 Magnum were 11 BHN.

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Re: cast bullets

Post by jmdavis on 8/1/2017, 2:19 pm

I don't thnk that Keith used a 97/3 mix for the 44 mag. I could be wrong, but I want to say that his high velocity bullets were harder, at least Lyman #2 hardness.


Added later, Keith's alloy was 16:1 or 15 lbs of lead per lb of tin. That's more like 93/7 not 97/3. 97/3 would be over 24:1.
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Re: cast bullets

Post by USSR on 8/1/2017, 4:27 pm

16:1 alloy has a BHN of 11.   Check it out.

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Re: cast bullets

Post by james r chapman on 8/1/2017, 8:03 pm

When Elmer and I were casting bullets, there were no wheelweights.
just good ol' 16:1. the key Elmer told me was the lube, and proper sizing to match bores and throats, getting a good seal to contain the pressure.
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Re: cast bullets

Post by USSR on 8/1/2017, 8:19 pm

Jim,

I've got a connection to Elmer as well, athough very, very distant.   As a kid, I wrote to Elmer when I believe he was an editor for the American Rifleman magazine.   Amazingly, he wrote me back giving me advice on reloading the .357 Magnum and .30-06.   Man, was he a lousy typist. Smile 
 
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Re: cast bullets

Post by james r chapman on 8/1/2017, 8:24 pm

as I am a great liar... lol
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Re: cast bullets

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