i had 12ga with choke tubes for a while (winchoke/browning std invector type). the frame and rear lug with replaceable plate is like that on parker bros. gun and front lump has spring thingy thing like winchester model 21. the 23 is a&d system gun while the 201 is not. nice quality reliable gun but just could not warm up to it like i did to my sterlingworth ejector.