Priming compounds and primers introduction – ballistics static electricity definition science


Short history of priming compounds. gas examples matter The earliest priming compound was almost certainly mercury fulminate as used in the Forsythe scent bottle priming system which was introduced around 1806. z gas ensenada telefono This compound is highly sensitive and liable to spontaneously explode for no apparent reason. tgas advisors company profile As a result, the Forsythe scent bottle, which required a considerable quantity of this compound to be carried in a container on the side of the pistol, did not achieve a great deal of popularity.

The first real percussion cap (a small metal cup containing the priming composition which was placed on a nipple at the rear of the barrel) was introduced by Joshua Shaw in 1814 and contained mercury fulminate. 76 gas credit card login As a result of the unpredictability of plain mercury fulminate, it was superseded in 1818 by a mixture of mercury fulminate, potassium chlorate, sulfur and charcoal. The residues produced by this mixture were, however, still terribly corrosive, requiring the weapon to be cleaned immediately after firing.

It was found that purification of the mercury fulminate would lead to a more stable compound, and in 1873, a mixture of mercury fulminate, potassium chlorate, glass dust and gum arabic became the standard US military priming compound. k electric bill payment online This mixture suffered from two major drawbacks: (i) the mercury tended to make the brass cartridge cases brittle, which led to case failure on firing and dangerous leakage of high-pressure gas from the breech of the weapon; and (ii) the potassium chlorate left terribly corrosive residues in the bore of the weapon after firing.

Up to early 2000, the most common primer composition encountered was still the lead styphenate, barium nitrate, antimony sulfide and tetrazine type. electricity 101 presentation In this priming compound, lead styphenate and tetrazine are the sensitive explosive ingredients; barium nitrate provides additional oxygen to increase the temperature of the flame, and antimony sulfide acts as a fuel to prolong the burning time. bad gas 6 weeks pregnant Aluminium, and occasionally magnesium, can also be encountered, but mainly in the higher-powered magnum pistol or rifle calibres.

Lead-free and non-toxic primers. 3 gases in the atmosphere It began to become apparent in the early 1970s that in heavily used training facilities, the range personnel were suffering from the symptoms of lead poisoning. Whilst a large proportion of this lead was being volatilized from the base of the bullets, a portion was obviously coming from the lead styphenate primer.

The US National Bureau of Standards claims that when lead-based primers are used, 80% of airborne lead on firing ranges comes from the projectile and 20% comes from the priming composition. These percentages obviously depend on whether the bullet is plain lead or jacketed. In the case of a non- jacketed bullet, the rifling will strip lead from the bullet’ s surface, thus dramatically increasing the percentage of non-primer-based airborne lead.

The problem was first solved in the early 1980s by Geco, who released a zinc- and titanium – based primer which they called " Sintox’. Since then, there have been a number of other lead-free primers produced by, for example, CCI Blazer, Speer, Federal and Winchester (Haag, 1995). The exact composition of the priming compounds used is not available, although SEM/EDX (scanning electron microscope/energy dispersive X-ray) analysis generally shows the presence of strontium in the Speer and Blazer cartridges, potassium in the Winchester cartridges and calcium and silicon in the Federal cartridges.