I ordered some tin for my bullets

[David LaPell]

I have ordered some tin to help my $358156 HP bullets that were fragmenting, but how much tin by weight should I add say if I am using my little Lee ladle pot which holds 4 pounds altogether. So for four pounds say of wheelweights or WW-lead mix how much by weight should I add of tin?

[Shuz]

To minimize fragmenting on my hp boolits I cast from an alloy that is 1/2 ww's(clip on) and 1/2 pure lead with the addition of 1 to 2% tin. IMHO it's the antimony in wheel weights that causes the fragmentation;not the absence of tin.

[montana_charlie]

To eliminate the brittleness caused by the antimony, the amount of tin should equal the antimony content.
In an alloy that is based on half-n-half lead and WW, adding 2% of tin equals the 2% of antimony already in the mix.

If you are using straight WW, you need a total of 4% tin. The alloy may already contain .5% so you would add enough to bring it up to 4%. Four pounds of WW would need 2.24 ounces of tin to reach the 4% level - which matches the antimony content.
You could then cut the mix with pure lead to adjust the hardness, but the antimony/tin content would remain in balance.

Adding that much tin to WW would not increase hardness more than two Brinell numbers, but would greatly improve the malleability of the alloy.

For comparison, adding one more percent of antimony and one more percent of tin would bring your WW up to Lyman #2 alloy ... a 15 BHN alloy developed specifically for bullet making.

CM

[Larry Gibson]

To minimize fragmenting on my hp boolits I cast from an alloy that is 1/2 ww's(clip on) and 1/2 pure lead with the addition of 1 to 2% tin. IMHO it's the antimony in wheel weights that causes the fragmentation;not the absence of tin.

+1.

Additionally I would suggest you don't use the COWWs for the 358156HPs. I quit using it years ago in my own 358156HPs. I suggest you use the lead and make up 30-1 alloy if your velocities are 1000 - 1250 fps; that would be 2 oz of tin added to just under the 4 lbs lead in your pot. Cast some of those and test them. I use a 20 -1 alloy (add 3.2 oz tin) for 1250 - 1400 fps and a 16 -1 alloy (add 4 oz tin) for 1400 - 1600 fps. The lead tin alloy will gve much better expansion charactoristics to your 358156HP.

Larry Gibson