A police -or wathever- with gun is a serious problem. Most of them are psicothic against many kinds of persons and have very serious familiar problems. The soldiers must make a lot of exercices with his weapons putting it in his shoulders and managing it standing in front of his sargeants. It´s mostly to avoid psicothic problems. Each army has his own exercices that involve several movements until the weapon is pointing in front of them and fastly another one to release the weapon.
As far as I´m concerned in France the police put his hands arround the neck making the hanged rictus and the soldiers patrol the streets with militar weapons. Very, very fast to show his militar power. In Spain there aren´t soldiers in my region but the police go with couples saying things like "nothing" and then touching his guns and use to make phalic references to his gun with stupid smiles and so.
In GB there are much more polite in the management of his weapons not pointing you but this can be meaninless if the weapons are used to kill.
One communist told me that when was soldier in Mauritania the sargeant asked the soldiers "Does anyone knows anything about plumberie?" and the more youths make a step in front and say "Me! Me! Me! ..." and then were ordered to dig the graves of the death spainish soldiers to carry them to Spain again -Notice I´m antimilitarist- and one crazy legionar told me about a sargeant in Mauritania also that one night go to bitches and was found with the neck cut and the penis and bollocks in his mouth. Well I prefer to use my bare hands, not any weapon.