"Modern" .44 Colt dates to the mid 90s, when Armi San Marco offered the first of the Richards conversions chambered in the round, (I still have one of these) Uberti picked it up soon after ASM went under, offering it in their various open top/conversion revolvers. The last few years they've simply ran the chambers further out to accommodate .44 spl brass. Black Hills offered the caliber for nearly 20 years, only dropping it a couple of years ago, and Starline still makes the brass. My ASM RIchards and both my Uberti .44 Open Tops will only accept the Colt length brass or shorter. THe number of ASM/Uberti .44 Colts far exceeds the orginal 8000 or so of Colts production in the 1870s.