Monday, April 4, 2011

Annealing Lead Alloy for Softer Boolits - The Approach

Since my supplier of pure lead is drying, the problem is how get bullets of BHN 8 or less casting with wheel weights.  Softer lead bullets provide consistent accuracy, as compared to BHN 11, or 16 or harder.  A well designed bullet, sized to perform in your revolver (often .360 works, but some revolvers vary) can produce great groups, even if it's a harder than BHN 8.  However, softer alloys produce better groups, and do it more consistently.

Strange as it sounds, the process to soften wheel weight alloy bullets is much like the process to harden them.  The difference is, to soften the bullets, they don't get quenched in cold water.

The goal of the upcoming test, is to verify that bullets can be softened to BHN 8, or as close to it as possible.  If they can be softened, does it last more than a few days or does it last for weeks.  Since it takes a long time to verify test results, it will be about a month before I can post the resulting data.

The process is to heat the bullets in the oven, then turn it off and let them cool to room temp.  It can take a couple of hours to cool slowly.

The initial results will be for pure wheel weights, additional tests will verify the impact of adding additional tin.  Which is reported to soften the bullets even more.  Pretty great if it all works out.

The planned test will:

1) Heat bullets in the oven, set to 450 degrees, for 30 min
2) Turn it off, let the entire oven with bullets inside cool to room temp
3) Test the bullets hardness before heating, after heating and then at 7 day intervals
4) Report the results here

To achieve the best accuracy, shooting a softer alloy makes all the difference.  That is, in 357 magnums of course.  Not that I'm closed minded, but it is the most fun caliber to cast, handload and shoot, bar none.

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