Here are three different magazines. The first is the extruded WWII style magazine, the second a nickel plated Swiss and the stainless from my AIMCO post Stoeger. I could not put the older magazines in the AIMCO, and the AIMCO definitely would not fit my BYF 42. It is too thick. The magazine base on the AIMCO looks like wood, but appears to be and feels like plastic...