Every manufacturer...and sometimes shoes by the same manufacturer...seem to fit differently. Don't purchase by size, purchase by actual fit. Make sure that there is enough room in the toe box to wiggle your toes wearing your normal weight sock, but that the rest of the shoe still fits snug enough to keep it from moving around and causing blisters or sores.
If buying for winter use, make sure you try them on using your winter weight sock(s).
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey