35 to 1 casts smaller boolit than 50/50 or WW's

[Ohio Rusty]

Last week I cast up some 35 to 1 (Pure lead to tin) 358439's. I was going to load in 38's as a carry round as they weigh 155 grains. The softer alloy would expand better at +P velocities. In the past I cast up some from 50/50 alloy (WW's/pure) for a hunting round for the contender.

To my surprise last evening, I ran a few of the 35 to 1 alloy boolits thru my Lee sizer (.358), and the 35 to 1 boolits didn't hardly touch the walls of the sizer and went right thru with little or no resistance. So I tried some of the 358439's in 50/50 alloy and pure WW alloy, and both of those had resistance and resized -- evident by the shiny mirror like sizing on the boolit lands.

I would have thought that almost pure lead boolits would be bigger as they are more dense, but the opposite is true, they come out smaller. All these boolits are air and age hardened. This is an interesting find about alloys.
Ohio Rusty ><>

[geargnasher]

Pure will always cast smaller, linotype will be near the top for large in the realm of practical cast boolit alloys. The neat thing about pure lead is it will not age harden, temper, or grow. 35:1 is close enough to pure that the only difference you might note is it will be slightly harder, and MUCH easier to cast.

Gear

[nicholst55]

So on a related note, it appears that Lee intends their molds to be used with 10:1 lead/tin alloy - at least, that's what Lyman used with all of the Lee boolits they tested in their new (4th edition) Cast Bullet book. If one were to cast with a 'harder' lead/antimony/tin alloy like Lyman's #2 or linotype, would the Lee mold be expected to cast a larger diameter boolit?

Back before WWII, 10:1 was considered a relatively very hard bullet.