Notes from the Lab: .475 Linebaugh (Rifle) The .475 Linebaugh was developed in 1988 by custom revolver gunsmith John Linebaugh and created by cutting down .45-70 cases to 1.400 inches and necking them to accept .475-inch bullets. The new wildcat could propel a 430-grain cast bullet over 1,400 fps from a revolver with a 5 ½-inch barrel, and proved capable to take any game animal on Earth, including elephant. Linebaugh’s revolvers were primarily based on the Ruger New Model Blackhawk Bisley with the cylinder window being enlarged and a new five-shot cylinder and barrel installed. So modified, these guns easily housed the large .45-70 rim diameter of .608 inch. In 1998, Tim Sundles of Buffalo Bore Ammunition introduced .475 Linebaugh factory ammunition. However, in an effort to persuade Freedom Arms to chamber it in the excellent Model 83 single-action revolver, the .475 case had to be modified to work in the comparatively compact cylinder. This resulted in reducing the rim diameter to .540 inch, and the bullet nose and overall cartridge length were also shortened. The new modified cartridge still works correctly in custom converted Ruger revolvers and the Freedom Arms Model 757 revolver. Hornady Manufacturing offers factory ammunition. Due to the larger rim diameter, cut down .45-70 cases should not be used for assembling handloads in rifles, such as the Ruger No. 1 used herein, or converted Marlin leverguns, as the extractor is the incorrect size and cartridges will not chamber properly. Rather, use commercial .475 Linebaugh cases with head stamps marked “BBA,” HORNADY, or “Starline”, which are of top quality, offer long life and will function flawlessly in rifles and revolvers. Factory loads in revolvers generally push a 400-grain jacketed bullet around 1,300 fps, while 430-grain cast bullets reach 1,400 fps. In longer rifle barrels, such as the Ruger No. 1, velocities can reach 1,650 to 1,800 fps. Bullets should be seated to their correct depth, and then a heavy crimp applied. The accompanying data was fired using CCI 350 Large Pistol Magnum primers. Do not use large rifle or large rifle magnum primers with the accompanying data or pressures will rise significantly. .