Help ID Rimfire Cartridge

Please help ID this copper rimfire.cartridge case.
Case length: 53 MM
Case diameter: 13 MM
Rim diameter: 15 MM
Headstamp, clockwise from 12 o’clock: R 81 F 11

Thanks, Terry




What you show in your photo is not a rimfire cartridge case. Instead it is U.S. Military inside primed (Benet-primed) centerfire .45-70 cartridge case manufactured by Frankford Arsenal 11/1881, “R” indicates rifle load as opposed to a carbine load.

See: for some nice photos and additional information.


Thank you so much for the lightning quick response.