tannerite

Tannerite is a brand of binary explosive targets used for firearms practice and sold in kit form. The targets comprise a combination of oxidizers and a fuel — primarily aluminum powder — that is supplied as two separate components that are mixed by the user. The combination is relatively stable when subjected to forces less severe than a high-velocity bullet impact, such as a hammer blow, being dropped, or impact from a low-velocity bullet or shotgun blast. It is also designed to be non-flammable — the reaction cannot be triggered by a burning fuse or electricity.
Because it is sold as two separate components, it can be transported and sold in many places without the legal restrictions that would otherwise apply to explosives. The term "tannerite" is often used to refer to the mixture itself, and other reactive targets and combination explosives are often generically referred to as tannerite.

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