The Army, Navy, Air Force, and Special Forces along with other military organizations have mandated the reduction of ozone depleting chemicals (ODC). It is essential that these materials be replaced with solvent-free or solvent-safe case mouth sealants.

The goal of this program is to eliminate and replace the series of ODCs for small- and medium-caliber ammunition with better alternatives. These materials also would be applicable for threaded and fitted material components such as fuzes.

Efforts were aimed at testing and documenting the compatibility, reliability, and durability of ODCs that also met all of the ammunition acceptance requirements. Promising candidates then were subjected to functional testing and characterization as well as numerous acceptance evaluations. The initial selection of commercial materials was based on a study of mechanical, chemical, and physical property data as well as manufacturer recommendations.

An industry search was conducted into potential alternatives, and “fast track” testing was conducted. More than 50 candidates were down selected based on application ability, and the best candidates under went chemical analysis. Through the down selection process, Hernon 34201, a waterborne asphalt (paraffin) modified with a styrene/acrylate copolymer with plasticizers/fillers, was chosen. The material behaves similarly to previously existing sealant materials. Weapon compatibility, reliability, and durability testing was conducted for Hernon 34201. The project was completed in FY 1996.

Through the use of this technology, significant amounts of sealants with ODCs would be eliminated. Economic benefits would include reduced costs, increased production rates, reduced scrap ammunition (estimated at $2 million per year), and reduced lot rejection rate (which averages 6 percent annually). Other benefits would include reduced misfires and hangfires, decreased damage to weapon systems and vehicles, and improved personnel safety.