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Discussion Starter #1 (Edited)
I'm just starting to learn about casting, so please bear with me. :confused:

Most of the info that I have seen posted and published says that anything more than 2% tin in an alloy is a waste of tin and money. However, I have noticed some posts in the archives here that mention matching the amount of tin and antimony (ex: 3% Antimony and 3% Tin) will help the alloy retain its ductile (sp?) qualities and it will not be as brittle as Linotype; thus, the alloy with equal amounts of tin and antimony will be less likely than linotype to shatter when encountering heavy bone and may actually expand.

Am I reading this right, or am I off base here. If this is true than it seems that this would be an excellant alloy for larger North American game such as Elk, Moose, and Bears.
 

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Beartooth Regular
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Hi Matt,

The only thing I rely on Tin to do is aid mold fillout. It breaks the surface tension of the alloy during pouring and allows it to fill out the mold better.

Lead actually aids alloy ductility in the right proportions with Antimony or Tin added as an alloy "Hardener".

A Tin/Lead Alloy will heat treat but reverts back to it's original hardness quite quickly. A Lead/Antimony alloy will heat treat and hold it's hardness considerably longer.

Tin/Lead alloys are still popular with a number of shooters, especially black powder cartridge shooters. Tin has become an expensive ingredient to an alloy which is why you won't find much of it in many scrap alloys like WW's.

High Antimony and High Tin alloys, in relation to the amount of Lead, can be quite brittle with the High Antimonial alloy the most brittle and the High Tin alloy being somewhat more ductile. Linotype is an example of a High Antimonial alloy.

This is why heat treatment is a worthwhile pursuit because you can use a low percentage Antimonial alloy like WW's and make a very hard but ductile bullet from it.

Hope I didn't confuse you further. ;)


Regards
 

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The Hog Whisperer (Administrator)
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Dutch, you'll see from the link that Contender posted that you won't get much expansion to begin with. That bullet mush have hit something pretty hard (a big bone) to even expand at all.

I've seen a lot of photos of 'penetration tests' where hard cast bullets like Marshall's were fired into wet newsprint. Except for the rifling marks, and missing lube, most of them looked like you could load them up again.

The point is that you can't count on expansion with a good hard cast bullet unless you can be sure to hit a solid bone, and in that case, you don't need expansion at all (flying bone fragments will make a heck of a wound channel).

If you really want to get a little expansion you can harden the bullets, then soften the noses with a torch. There is some information on the forum somewhere about doing this. Haven't gotten around to trying this. Also some people cast soft noses on a harder base.

It all sounds quite interesting, but.... a careful look at the wound channels made by the WFNs, etc., has totally convinced me that expansion isn't even desireable with anything over .35 cal. Under that (say .30 cal for rifles) then I would think it would be helpful.

One of these days I am going to take some pictures with my digital camera during an 'autopsy' which will may be helpful in understanding the wound channels of one type of bullet vs. another.

If you do want some expanding bullets for rifles, best bet would be a lead/tin alloy with not much antimony. You'll get some bore fouling, but not much to worry about for a few hunting shots. A gas check will help a lot with that too. If I wanted some expanding bullets for my .30-06 that's the direction I would go.

Antimony is very brittle compared to either tin or lead. Pure lead is quite ductile - you can pound a muzzleloader roundball into a big flat saucer without any of it coming off. Tin is somewhere in the middle. Now, once you start combining the metals, the properties of the alloy aren't totally predictable, hence the hammer test.

Good luck.
 
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