The .44 Automag was originally created in the late 60's by the Pasadena Corporation. After the Pasadena days, several companies had their own version of the firearm, including: TDE North Hollywood, TDE El Monte, High Standard, TDE / OMC, and AMT.
Harry had received it as a gift. The grateful husband of a hostage and potential murder victim was a master gunsmith. A few months after Harry had rescued his wife from the mess of a botched bank robbery, he had sent him the boxed gun and a card that read, "You saved my wife's life. Maybe this will help to save yours.".
In his time as a cop, Harry had never accepted a thing, not even a free cup of coffee. But he accepted this gift.