The present report summarizes and interprets the results from time series of eight years of studies showing leaching of heavy metals from small arms ammunition bullets in bullet trap sand. In short, the study is based on chemical analyses of leachate from four lysimeters in the field, three of which were filled with sand contaminated with different combinations of lead and steel bullets. The fourth lysimeter has been filled with unaffected sand and is used as a reference. A conclusion is that in a possible future transition to lead-free steel-based ammunition, a greater leakage of copper and zinc should be expected,in particular when older bullet traps are used. This also entails the risk of increased leaching of lead from older lead bullets. Firing steel ammunition in a natural environment can cause an increased leakage of copper and zinc from the projectiles, which may negatively affect soil organisms.