How Much Shrinkage?

[ChristopherO]

A new Lee 457-405 mold came in last week and yesterday morning I smelted another 20lb of soft plumber's lead and cast a handful to see how they would measure. They came out quite large, .460+. That is much bigger in diameter than the hot glue slugs I cast out of that mold last week to fool with. Those only came in at .456 at best.
Lead this soft isn't what I intend to use for these boolits but I am wondering if I use, say, Lyman #2 if these boolits will measure noticeably smaller in diameter? I have been fully ready to lap this mold to get it where I wanted it to be and am now thinking that may not be necessary. These lee slugs are not perfectly uniform, cavity to cavity, nor are they totally concentric around, yet the .459 sizer die appears to take care of that easy enough.
Should I leave well enough alone and find out what a higher BHN will yield?

[lobowolf761]

Let it be and try the harder alloy first. No sense in messing up the mould if you don't need to.

[Yodogsandman]

Your bullet will be larger with a harder alloy than pure lead. Check out Table 2 from the bottom of the following link...

http://www.lasc.us/SuperHard.htm

[mdi]

Another factor in cast bullet diameter is the temperature of the mold and the temperature of the melt. I have gotten slightly larger bullets from warm mold and melt on the cooler side...

[dubber123]

I'd make sure the mold was burr free, and closing fully first. If it casts even close to round, .460" out of soft lead would make most LEE buyers ecstatic. I'd expect a harder alloy with a higher tin/antimony content to cast even larger. Dependent on the particular firearm, fatter is better. My Marlin gets .462" for example.

[John Boy]

http://www.lasc.us/new-2.gifFrom Ingot to Target: A Cast Bullet Guide for Handgunners
(http://www.lasc.us/Fryxell_Book_Contents.htm)
(http://www.lasc.us/Fryxell_Book_Contents.htm)
Alloy shrinkage of cast bullets
http://www.lasc.us/CastBulletNotes.htm