US Patent 8216401 Lead-free primers

Embodiments of the present subject matter provide an improved percussion primer composition and improved hot-wire igniter acceptor, wherein lead styphnate is replaced with a lead-free material, 4,6-dinitro-7-hydroxybenzofuroxan, potassium salt (KDNP). Embodiments of the percussion primer composition include KDNP, a sensitizer, an oxidizer, calcium silicide, a fuel, and a binder. Embodiments of the hot-wire igniter device include a bridgewire, an acceptor, and an output, where KDNP is the acceptor. Power supply may be in the form of constant current/voltage or current flow from a capacitor discharge. Certain embodiments utilize a variety of output formulations, such as BKNO3, black powder, and Red Dot double base propellant.