If in a parade and wearing Service Dress uniform, is there anything against carrying (whether open carry/concealed)?

First, I am a North Carolina Conceal Carry Instructor and North Carolina is an Open Carry State AND I work in the Firearms Industry selling AR-15s. SO I am in no way against the AR15....
IF you are standing there in Service Dress with an AR15 slung over your shoulder you are wrong as two boys....well, you get the idea.
It puts the wrong message out there. Just because you CAN do something does not mean that you SHOULD do it. Don't make the uninformed public think that you and me and the rest of the AR15 owning population are paranoid fruitloops. While I think that open carry of a rifle is not appropriate, open or conceal carry of a sidearm is just fine. I carry a M1911 everyday as part of my job, and I have no problem going into places where I do business open carry nor do those business owners have a problem with me carrying.

SSG Roger Ayscue
I live in Arizona where we have Constitutional Carry, both open and concealed. I normally carry concealed, but that's my personal choice. I have nothing against open carry. I choose to carry concealed because I figure that if I'm ever in a mass shooter-type situation, I won't be targeted right away, and I'll have time to plan my response.

I would recommend that any AR-15 carried be a close visual match of either an M16-series rifle or M4-series carbine, SSG Roger Ayscue. A highly customized AR with free-floated barrel would seem very inappropriate in that scenario.

I agree...Stainless Kreiger Barrel or Precision stock would seem so pretentious as to ... Well, it is just "Simply Not Cricket Old Boy"

Make sure you consult your state laws and local ordinances. The bulk of cities/towns/states have a clause against carrying either open or concealed to or during a parade.