Density-enhanced compositions that are comprised of at least iron and tungsten, and articles, including firearm projectiles, formed therefrom. The articles have a density that exceeds that of steel, and which may be less than, equal to, or greater than that of lead. In some embodiments, iron is the majority component and tungsten is a minority component, with steel optionally forming a portion of the iron-containing component. In some embodiments, the article includes at least one additional minority component, such as one or more of nickel, manganese, tin, carbon, steel, chromium, molybdenum, silicon, aluminum, zinc, copper, potassium, sulfur, vanadium, and/or titanium. In some embodiments, the article is cast or otherwise formed from molten material, and in some embodiments the article is formed via powder metallurgy. In some embodiments, the article is firearm shot, a firearm slug, or a bullet.