7.62x39 Corrosive: The Fiery Soviet Surplus Survivor What is Corrosive Ammo? Corrosive ammo is a bit of a misnomer as the ammo itself is not corrosive, however, the primers in this ammo contain a priming compound that utilizes corrosive salts. Once fired, these corrosive salts will be deposited in the barrel, gas system, bolt, and chamber of your firearm and begin to corrode unless properly and quickly removed. Evolution of Corrosive Primers: Between 1808 and 1812, the Swiss gunsmith Jean Samuel Pauley created the first centerfire cartridge which utilized a percussion cap as the primer. A percussion cap utilizes mercury fulminate as the priming compound as it is very effective at igniting black powder. Although mercury fulminate excels at igniting black powder, smokeless powder exposed the shortcomings of the percussion cap. Mercury fulminate will slowly decompose over time, meaning that eventually, the percussion cap will lack the energy required to ignite the smokeles...