I don't think that penguin undersands the difference between the M1 Garand and the M1 carbine. FWIW all 3 shoot the same diameter slug, 7.62. (.30 cal) The M14 and the Garand shoot a much heavier 7.62 slug in the 147 to 150 grain range, the M1 Carbine uses the 110 gr. short stubby bullet.