I have just finished making up some brass for a original spencer,the brass is made to original rim diameter fromm 50-70 brass,and just for somthing to do I wanted to see how much over sized for the Armi Sports 56-50 it would be ,to my suprise it fits perfectly in my rifle,if this is the case in all AS 56-50s starline is missing 3/4 of its market for 56-50 brass by not going with the original rim diameter,I know a lot of people youse there brass in original Spencers with no trouble including me ,but that little bit extra rim diameter would be very welcome by most shooters of original and Ramano Spencers,and they would sell more so we mite not have to go through brass droughts