Abstract: A primer mix which contains from 26 to 66 weight percent titanium and from 74 to 44 weight percent potassium perchlorate having a density of from 68 to 81 percent of crystal density such that the mix is stable at high temperature up to 525.degree. F. for more than 100 hours without degradation and requires a relatively high amount of impact energy greater than 4 ft.-lbs. in order to ignite it. Alternatively, the primer mix contains from 40 to 74 weight percent zirconium and from 60 to 26 weight percent potassium perchlorate having the above density. The primer mix is used in a percussion primer for initiating combustion or in a percussion initiator for detonating a high-order explosive, as used for example within wellbores in the oil and gas industry.