Cimarron Lightning 41 Colt 6.5" Barrel Case Hardened Pre-War Standard Blue Finish Revolver 1-Piece Walnut Grip Md: CA3057

It was a lengthened version of the earlier centerfire .41 Short Colt, which was made to duplicate the dimensions of the even earlier .41 Short rimfire. The front of the bullet was about 0.406–0.408? OD, the same as the case. The barrel was about 0.404–0.406? groove diameter. The bullet lubrication was outside the case. The base of the bullet was smaller in diameter to fit inside the case. In the mid-1890s, Colt redesigned the cartridge. They reduced the entire diameter of the bullet to 0.386" OD and lengthened the brass case in order to put both the bullet and its lubrication inside the case. The overall length of both loaded cartridges was about the same. The barrel of the revolver was reduced slightly to match the more popular .38-40 at 0.400–0.401? groove diameter this was probably done for manufacturing reasons, not accuracy reasons. — Wholesale Hunter