ABSTRACT
One of the most common methods for determining firing distance based on the nitrite distribution pattern is the Walker test, which was first reported in the literature in 1937. The Walker test is sensitive to inorganic nitrite ion. Certain types of smokeless powder ammunition do not contain inorganic nitrite as an oxidizing agent in the primer and as a result no nitrite distribution pattern is obtained with the Walker test even at near contact firing distances. In the modified arrangement the freshly sensitized, moist photographic paper has absorbed a sufficient amount of acetic acid to permit the diazotization and coupling reactions to occur. Most types of modern gunpowder consist of smokeless powder. Single base smokeless powder contains nitrocellulose and double base smokeless powder contains nitrocellulose and nitroglycerins. Nitrocellulose and nitroglycerine which contain organic nitro groups are a partial source of inorganic nitrite ion.
