of the same cartridge in both a pistol and a rifle. According to rumor at the time, this was owing to early .45 Colt cartridges having a very narrow rim and causing ejection issues from a rifle chamber. Today, modern Winchesters, Marlins, and other replicas have remedied this omission almost 50 years after the fact, and the .45 Colt is now available in modern lever-action rifles. While this aforementioned rumor has been one of the numerous arguments used to explain the lack of a rifle chambered in .45 Colt, it may have simply been a case of Colt refusing to authorize the use of their patented .45 Colt cartridge in other manufacturers’ arms. Only after the expiration of Colt‘s original patents for the .45 Colt did it become available in a rifle. This, however, does not explain the absence of a .45 Colt chambering (or indeed any of Colt's own cartridges) in the Colt-Burgess lever-action or Colt Lightning slide-action rifles. Thus lending more credence to the rumored basic problem with Colt's revolver cartridges when used in rifles. (The modern .45 Colt cartridge rim is still narrow, but features an extractor groove cut into the base of the case, a feature common to most modern cartridges but not at all common in the late 19th century.) The U.S. Army's .45 Colt round used in its M1909 revolver, which had a barrel of , fired a bullet at a muzzle velocity of , giving a muzzle energy of . Today's standard factory loads develop around of muzzle energy at about , making it roughly equivalent to modern .45 ACP loads. There are Cowboy Action Shooting loads which develop muzzle velocities of around . Cartridges of the World states that .45 Colt should never be loaded to more than in blackpowder revolvers. High pressure ammunition Some handloads and factory-manufactured cartridges put this round in the same class as the .44 Magnum, using specially made revolvers. These loads cannot be used in any original Colt Single Action Army or replica thereof, such as those produced by Uberti, Beretta, the Taurus Gaucho, or the Ruger New Vaquero, as these guns are built on the smaller frame with thinner cylinder walls. These loads should be used only in modern large-frame revolvers such as the Ruger Blackhawk, Ruger Redhawk, and the original large frame Ruger Vaquero (sometimes referred to as the "Old Model" to differentiate it from