Some rifles marked .223 can handle .556. The Ruger Mini 14 is an example.
Both rounds fire the same projectile and basically have the same muzzle velocity so really no difference in the end unless you are looking for maximum accuracy at very long distances. I have never heard anyone choose one over the other based on one being mil spec!
So do you feel that civilians should not own a weapon that can fire a mil spec round? If so, you should also avoid any gun chambered in .45 .40 30.06 762x51 or 9mm as well since the military uses or has used those as well. .25ACP is a good bet since They would never use that one!
@Bomber So you're saying that because I admitted to having been on anti for a short period in my life I'll most likely be denied?
For the record, the detective that I'm in touch with has A) said that I have as much time as needed to get a doctor's note, and B) asked simply for a letter, not a full forensic psychological assessment.
Either way - given that no doctor's psychiatrists/psychologists I've called seem willing to write the note. It seems like a forensic evaluation is the only option.
That being said, I'm a bit reluctant to spend the money if you think I'm going to get denied regardless of the findings.