Police are becoming increasingly worried about the number of powerful, large-calibre air rifles being brought into the country. The guns can be sold without a licence to people over 18 and at short range could easily kill a person. The guns are marketed in the United States as "serious hunting guns" and are powered by compressed air and charged from a scuba tank. They fire a heavy .50 calibre lead slug at about 600 feet per second, and can be bought for as little as... (GunPolicy.org)