"National match" bolt carriers.... are they "commercial" or "mil spec" diameter?

[LRRPF52]

Gene I think you are confusing the buffer tube for CAR type stocks.

Nope. Young's makes NM bolt carriers that have had some differences in diameter in the past...read above. This isn't a mistaken question about extension tube diameters, since nobody makes a National Match extension tube for competition guns, as they use full-length stocks anyway in high-power and DCM.