In the late 1960's we laughed at the M16 because it didn't look military and one of the favorite references was "made by Mattel". To anyone familiar with hunting the 5.56mm cartridge felt like a joke when compared to the 30-06 or 308.
You will not find a semi-automatic 223 that doesn't look like a military rifle because there is no incentive to develop a rifle for which a mature government financed design exists. That is unless it a "new" military design. Even Bill Ruger, when developing the "mini 14" simply scaled the action from the 308 M14 to the 223/5.56 cartridge.