What the manufacture date for Harrington Richardson serial number A126454?

The manufacture date for Harrington & Richardson (H&R) firearms can typically be determined using the serial number. For the serial number A126454, it is likely that the firearm was produced in the early to mid-1950s, as H&R used the "A" prefix during that period. For a more precise date, consulting a specific H&R serial number reference guide or contacting a firearms historian could provide additional details.