what kind of a gun would you use

find out what gun you would use if you were in the war. (possibilities, sniper rifle, rocket launcher, shotgun, or a pistol)

1 you are in a tight situation a man is 5 miles away how do you kill him
2 you are alone in base a group of 3 enemiesis coming after you how do you get them
3 you have to go out for a mission which gun do you take
4 theres four guys alone in a building at night they are the enemies were do you shoot from
5 you are in a helicopter and the enemy is below how would you kill them
6 the enemy is in their base they are guarding how do you kill them
7 you have some guys in a jet chasing your military jeep how do you kill them