Can't tell if it's R - P or R - - P, but this should help, see information in second paragraph. It's a Commercial/Civilian used headstsmp. Meaning the ammo was Commercial made, but Civilian and Military used.
R-P Remington-Peters – Lonoke, Arkansas (1970–present). Lonoke facility only produced centerfire ammo from 1970; took over rimfire production from Bridgeport in 1989.
R--P Remington Peters – Bridgeport, Connecticut (1960–1989). Bridgeport facility only produced rimfire ammo from 1970, then finally closed down in 1989.