I need a little help also My older ultramatch 308 fluted that was from a friend (don’t know the complete specs either)is stamped similar, as far as I know it’s a gen 1 ultramatch
Mine is similar , it’s a 18” 308 with flutes all the way, intermediate gas
Rainier 410k3
RMC D 10 S
Assuming yours reads rmc also, which is “rainier match chamber “ I think. D is for dpms (style?) 10= 1-10 twist I’m guessing , S is ?? Shilen?
Anymore info Mac?