will 20:1 cast like lyman #2 ?

[bigmike13]

I have a lyman 4 cavity pistol mold that the pervious owner said therw the right sized bullets with lyman #2. I was wondering if 20:1 would throw similarly sized bullets becuse of the tin content or does the antimony aide in the fill out as well? I ask becuase If I can have one alloy for my 45acp and 45-70 that would be ideal for my needs.

[lwknight]

Antimony , IME does not help with fill out at all. 20-1 should cast beautifully.
You should get a semi-hard cast but will soften some with age.
Lead shrinks when it cools and antimony will counteract the shrinkage because it actually grows when it crystalizes ( kinda like water to ice) and it is one of the most popular hardeners that will not age soften.
Even true #2 will soften a little because of the tin content but the antimony counteracts that as well by age hadening depending on the rate that the cast was cooled.

The 20 to 1 should be great for 45 ACP and best of all the boolits will not get the blue-grey fuzz and moldy looking for a very long time due to the tin all but stopping oxidation.

I don't know much on the 45-70 but I would think that it should be pretty OK and would be awesome if you paper patch.