For the Spring of 2009, Hornady announced the introduction of GMX bullets and factory loaded ammunition using these bullets. "GMX" stands for "Gilding Metal eXpanding." The GMX is a monolithic bullet along the lines of the Barnes Tipped TSX bullet, but with a red (rather than blue) plastic tip to initiate expansion. These are very sleek, boat-tail bullets with high ballistic coefficients, similar in shape to the popular Hornady SST bullets. Like all such monolithic bullets, they are longer for their caliber and weight than conventional lead core, jacketed bullets and intrude deeper into the cartridge case when seated for the same cartridge overall length. Unlike the 100% copper Barnes TSX bullet, Hornady's GMX is made from gilding metal, a 95% copper + 5% zinc alloy devised long ago to reduce copper fouling in gun barrels. Gilding metal is slightly harder than pure copper and superior to copper for bullet jackets.