Techniques can be divided into two general types: those involving reaction with the fingerprint deposit and those that involve reaction with the substrate. The most suitable techniques to visualize latent fingerprints on spent cartridge cases were found to be vacuum cyanoacrylate (with fluorescent staining) and selenious acid treatments. Both were used to investigate the postfiring recovery of fingermarks on spent cartridge cases from the ammunition and weapon systems encountered in terrorist casework in Northern Ireland. Only certain revolvers and the SLR rifle yielded identifiable ridge detail. The results of the study are borne out by casework experience. In general, loss of fingerprint ridge detail on a cartridge may be due to physical damage during the loading of the round or during ejection of the spent case; damage due to gaseous blowback during firing; or interference due to propellant by-products from gaseous blowback. Ridge detail recovery may also be affected by the type of round and the composition of the cartridge case. Tables, figures, references