In order to deal with complaints about bullets on army rifle ranges causing lead to get into the local ground water, the army is switching to tungsten bullets. The army uses 200 million 5.56mm M-16 bullets a year in training, plus another 200 million 7.62mm (for machine-guns) and 9mm (for pistols) rounds. The new tungsten round costs more initially, but is expected to eventually cost about the same as the older lead bullet cartridge. While soldiers wont notice the difference, the new bullet causes less barrel erosion and is slightly more accurate. The barrel erosion angle may save some replacement barrels in peacetime, when M-16 rifles are used a lot without risking loss in combat.