[FONT="]The cartridges in the box, with their raised 'U' headstamps, pin its production date down a little more precisely to between 1877 and 1878, the two years that UMC employed this headstamp. Prior to this, their rimfire cartridges were[/FONT][FONT="] unheadstamped; after 1878 they went about seven more years without a headstamp before the impressed 'U' that we are all so familiar with came into use in 1885, and continued to be used by UMC and and their successor Remington-UMC for the next hundred years or so.[/FONT]