I'm not even sure these are .45-70, but I'm curious what they are and who made 'em. I tried looking up headstamps online, but didn't really get anywhere. Should be easy for somebody who knows such things to ID them, I hope.
Was able to enlarge your photo........They were made by Frankford Arsenal........R = Rifle, 4 = April, 7? = 1870 something.......I can't make out the last digit of year, F = Frankford Arsenal. A good source for headstamp information and just about anything else you want to know about cartridges can be found here: www.cartridgecollectors.org