Dip-Casting Bullet Weight Experiments

[TexasMac]

Due to the previous results of my bullet weight experiments, which conflicted with normally accepted understandings of a homogeneous lead/tin alloy mixture, I decided to run some additional tests.

1st session:
To check the homogeneous nature of the alloy, the pot was filled with 20:1 alloy, fluxed & allowed to set for 7 hrs. Using the bottom pour feature, several bullets were cast & the lead/tin ratio measured. Then, by gently filling the ladle from the top of the alloy to minimize disturbing the alloy, several bullets were cast & the lead/tin ratio measured. The ratio of the alloy from the top of the pot was 18.5:1 and 19.5:1 from the bottom.

2nd session:
The above test was repeated after allowing the pot to set for an additional 8 hrs. The ratio of the alloy from the top & bottom of the pot was 19.5 & 19.7 respectively.

3rd session:
Finally, the test was repeated after letting the pot set overnight (approximately 12 hrs). The resulting alloy ratio from the top & bottom of the pot was 18.8 & 17.0 respectively.

The above results tend to support a homogeneous alloy versus what I measured in the earlier experiments for which I have no explanation. I’m beginning to wonder if unseen voids in the bullets affect the specific gravity (alloy ratio) measurements.

But I needed to cast up a batch of bullet for an upcoming match. So 60 bullets were cast while stirring the alloy. The result was a total weight spread of 0.8grs and the average lead/tin ratio measured at the start and finish was 20.2:1 +/- 0.2, which essentially confirmed my results from previous sessions when stirring the alloy while casting.

That’s it for me. I don’t plan on additional experiments on this subject. I’ll just be sure to stir the pot during future casting sessions. By the way, a forum member reading the results of my experiments referred me to an excellent article that was published in the Jan./Feb. 1981 issue of the Hanloader magazine. Titled, Weight Variations in Cast Bullets, it can be accessed at https://www.riflemagazine.com/magazine/P...artial.pdf

Wayne