Method providing self-dispensing additive from buffer blocks for use with a medium in a bullet trap

A method of providing an additive in a self-dispensing form for stabilizing a projectile-trapping medium and passivating spent projectiles trapped therein, comprising:

• selecting at least one dry component from the group consisting of low-solubility phosphate compounds, low-solubility aluminum compounds, iron compounds, sulfate compounds, and calcium carbonate;
• selecting at least one cementing material;
• providing water;
• mixing substantially stoichiometric amounts of said dry components,
• said cementing material, and said water to yield a workable paste;
• wherein said mixing substantially stoichiometric amounts of said dry components, said cementing material, and said water comprises mixing about one part by mass said low-solubility phosphate compound, about one part by mass said cementing material, and about 0.4 parts by mass said water;
• adding a quantity of an aqueous-based foam to said paste to form a slurry,
• wherein the quantity of said foam is sufficient to yield a density of said additive sufficiently high to prevent buoyancy of said additive and sufficiently low to prevent said additive from sinking in said projectile-trapping medium;
• casting said slurry in at least one mold suitable to establish said form;
• at least partially curing said slurry in said mold;
• and
• removing said cured slurry from said mold to yield said self-dispensing form.