.357mag with an 18” barrel performs like 30 carbine in an M1.
The matching caliber for your sidearm is an advantage.
The .357 outperforms the .30 carbine across the board. I’ve often wondered why the Army chose the old Pederson device cartridge as the jump off for its new carbine.
The .38 Super and .357 both existed at the time, and a rimless .357 would have substantially increased the potency of the M1 Carbine, with negligible increases to overall weight and magazine length.