In the hands of the average soldier, the M-16 was not only more lethal but more forgiving of poor marksmanship. Firing range instructors pointed out that with an M-16, any hit on the human profile target was scored as a “kill.” The M-16’s small-caliber, high-velocity bullet would do more damage than the once standard, slower and larger 30-caliber projectile. A single M-16 bullet was designed to take off a hand at the wrist or ricochet inside a body to cause more medically untreatable damage. Though the M-16 could be fully automatic, we were taught to use it in semi-automatic mode — in other words, like an AR-15.
"Therefore you pretend soldiers should be good citizens and surrender the too-deadly guns you own, for the public good!"
So your 1903A3 and Garand and such are just poor substitutes for the AR. And you can keep them until they decide they're also too dangerous for us peasants to own.