S&W has much weirdness in it's model number system, none as much as with the 45 Colt/45 ACP guns. Until after WWII, S&W only made 45 caliber guns as special order. After the war the Model of 1950 was available in three calibers, most were 44 Special, some were 45 ACP and a few were 45 Colt. The...