"Americans have the right and advantage of being armed - unlike the citizens of other countries whose governments are afraid to trust the people with arms." (James Madison, The Federalist Papers #46 at 243-244)
AR-15 Pistol. Such a sight would not be uncommon, as there are few gun regulations outside of New Rome. After 9/11, gun laws were reconsidered, but they are still very lax compared to most other western countries.