The M1/M2 Carbines themselves together with the .30 Carbine cartridge would have you outranged by AKMs, so together with the not very good magazines I would foresee a lot of getting raped any time you get engaged past its modest 200yd effective range.
Did not know it was as bad as that, but yes, a lot of the issues is just plain not hitting at all. On the M2 Carbine, the light weight, dropped stock, and high cyclic rate all make it a bit intense in full-auto fire, and having heard of many people trying to use the full-auto at extended ranges in said conflict, I imagine most never scoring a hit trying to shoot a Communist moving somewhere in the distance. .30 Carbine also is just not a powerhouse at long range, so even scoring a hit is likely to produce lacking results.
The carbine was great for CQB (especially in WW2 where most opponents had bolt-action rifles), and it would as designed give support personnel some kind of fighting chance or an attempt to cover an escape if they had the misfortune of bumping into a stray enemy, but in the infantry rifle role it's about as versatile as the FN P90, as in not, and I think that's what actually shows about its misuse in the Korean War. (I've genuinely seen people argue passionately/angrily that not only would the M2 have made a competitive 'assault rifle' if employed as such, I've heard people argue the P90 should replace the M4A1)