April 1, 2013, 07:27 PM | #1 |
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1:10 alloy question
As I understand a 1:10 alloy of lead and tin has a hardness of 11-12, I have read that after 20 days it will loss about 4 bhn for a hardness of 7-8 is this correct or is it harder when just cast?
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April 1, 2013, 07:57 PM | #2 | |
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I think you have part of that backwards.
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Not sure on the BHN. Tin is expensive and I'd almost start with a 1:20 mix or more. You never mentioned what you are casting for. It can make a difference. |
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April 1, 2013, 08:47 PM | #3 | |
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A lead tin alloy will get softer over time. How long i dont know. Alloys with antimony dont do this. Antimony, if water dropped, full hardness is reached later depending on the % of antimony. 2% about 2 weeks. 6% full hardness in 1 hour. http://www.keytometals.com/page.aspx...site=ktn&NM=88 Correction- Lead tin alloys-
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Last edited by 243winxb; April 3, 2013 at 11:08 AM. Reason: . Lead-tin alloys, for example, may recrystailize immediately and completely at room temperature |
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April 1, 2013, 10:59 PM | #4 |
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See below for actual BHN measurements:
Note that 1:10 will fall in the mid 8's. Note also that pure lead-tin alloys will neither harden nor soften with age. Nor will they respond to quenching. They are what they are. Add antimony, however, and you have a whole different ball game. Special note: Lyman#2 (5/5/90) is peculiar in that it also hits its BHN(~15) right away and stays there (mostly) irrespective of aging Last edited by mehavey; April 2, 2013 at 05:57 AM. |
April 3, 2013, 02:32 AM | #5 |
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I am loading a Uberti 1858 Remington revolver and am using a .45 conversion cylinder and am using a Lee 255 gr mold, when I cast using 1:20 or even 1:16 my bullets are in the 269 gr range using the 1:20 and 263 gr range using 1:16, I want softer bullets that weigh in around 255 gr and pure lead is to heavy for the molds I am using but if I can cast bullets using the 1:10 for a hardness of 11-12
and they will soften up to about a 8 bhn in a month it should work out great at my 750 fps velocity using 30 gr of KIK black powder. |
April 3, 2013, 06:56 AM | #6 |
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Hmmmm, my WW always end up around 12 or so.
I dont think I've even heard of 9 BHN clip on WW. Unless thats what the 50/50 bar means. My 50/50 clip on/pure lead bullets run about 9. I call it pure lead. Its stick on and lead pipe. |
April 3, 2013, 05:30 PM | #7 |
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Clip on wheel weights composition have varied over the years most likely based on alloy prices.
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April 3, 2013, 06:26 PM | #8 | |
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Believe me when I observe that with rare exception, alloys whose BHN numbers make-the-rounds on the internet are generally far softer than the "accepted" internet sources say they are. Numbers get repeated without actual test. If you want truth and no-kidding experience, swing over to castboolits.gunloads.com and open up the "Alloys" section. I will offer in closing that the truly "Hard-Cast" bullets by the professional caster are hard -- witness the ~24BHN of Beartooth's 400gr LFNGC at the bottom of the chart above. Last edited by mehavey; April 3, 2013 at 07:19 PM. |
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April 4, 2013, 07:07 AM | #9 | |
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You would have to add in some antimony to get your weights closer or you might look at a custom mold where you give them your preferred alloy and they will cut the mold to drop the proper weight bullet. Not the cheapest answer to your question, but if you want a 255gr bullet using your alloy about the only way to get there without adding in more antimony for a harder bullet. The closer to pure you go the heavier it is going to drop.
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