The 46 series, 46, 46A, 46B, and 46AN were all built on small ring pre=98 actions. The 146 and 246 were built on FN supplied actions that had the charger hump and thumbcut. SImpsons is notorious for mislabeling their product over the last several years.
Pappy, yours is a 640 series as are any using the FN Commercial Action.
