The 45-70 Govt. Project of Experiments poster is a unique replica of the actual hand sketched report of the project of experiments conducted at the National Armory (Springfield, MA) and drafted in March of 1875.This chart displays the various experiments conducted using the .45 caliber bullet weighing between 200 grains and 800 grains, with powder charges between 10 grains and 140 grains, and barrel lengths between 1 inch and 12 inches. The test results show that the .45 caliber cartridge loaded with 70 grains of black powder and a bullet weight of 405 grains was the optimal choice for the service cartridge in the 32-5/8” barreled model 1873 trapdoor Springfield rifle.