extruded wire will remove much of the wire that has noticeably different lead characteristics. After this point, the lead will maintain the same composition indefinitely.
The extruded wire is cut into segments to form slugs that will become bullets and bullet cores; these may be stockpiled in bins, possibly with slugs from different wires with different compositions, before they are assembled with other components to form cartridges. Bullets from multiple bins (also with different compositions) may be assembled into cartridges at the same time. That results in the possibility that different compositions of bullet lead are present in a single box of ammunition.
Details about the manufacturing and distribution of lead bullets and finished ammunition are largely unavailable. Therefore, distribution patterns and their effect on random matches cannot be estimated. Calculations can be used only to offer general guidance in assessing the significance of a finding that certain bullets are analytically indistinguishable.
The previously mentioned uncertainties arising from factors related to manufacturing make it difficult to define the size of a “source,” hereafter referred to as a compositionally indistinguishable volume of lead (CIVL). The analytically indistinguishable regions of wire could be considered a CIVL, but other wires extruded from billets from the same melt (assuming there was no additional material added to the melt while the lead was being poured) could also have regions that are analytically indistinguishable from this first wire (although this has not been confirmed by a quantitative, scientific study). A CIVL may range from approximately 70 lbs in a billet to 200,000 lbs in a melt. That is equivalent to 12,000 to 35 million .22 caliber bullets in a CIVL out of a total of 9 billion bullets produced each year.
Although it would be extraordinarily difficult—or impossible—for a large-scale industrial operation (smelter or bullet manufacturer) to purposefully duplicate a given CIVL, the possibility of recurrence of a composition over time as an occasional random event cannot be dismissed. Theoretically, the number of these that might repeat would depend in part on the number of elements measured, the