Gentlemen ......first let me apologize, my membership has expired. Concerning the regular frame 20 ga.In 1998 In bought my fourth L. C. Smith field grade 20 ga. with the serial # 12485 R . I don't remember much about the gun, especially the barrel lug size. I always thought it was a ' regular " frame". I no longer own said gun. Did the " R" in fact stand for regular ? Thanks for your time......Chuck