Now you can shoot inexpensive 22 Long Rifle cartridges in your .40 or .45 caliber single shot rifles including the Trapdoor Springfield. Practice with your competition rifle and hone your shooting skills. A great way to join the ranks of .22 silhouette shooting. This unit uses an ingenious shell holder adapter that holds the cartridge into the chamber of the liner. The shell holder then is struck by your rifles firing pin. Available only for the 40-65 Win., 40-90 SBN, 45-70, 45-90, 45-100, 45-110, 45-120 calibers ONLY.