I believe the 12ga guns,serial no.range 171,416 to 173,371 are "Hammer Guns" According to Brophy, 1913 "Hammerless Ejector guns" were serial no range from 215,616 to 216,939 or a total of 1323 guns produced in 10,12 and 16 ga. Considering the various gauges and Grades an estimate of 40 to 60 Specialty Ejector guns in the 3 gauges could be made. Specialty grades accounted for 3.8% of all Hammerless guns produced from 1913 to 1945