There are a total of 8 Long Shots
in the game, there is 1 in each mission. You need to shoot and kill the specific enemy collect them, you can replay any mission to shoot missed Long Shots and you can quit the mission as soon as you collect them.
A guide to ALL 110
collectibles can be found HERE
to all of the collectible videos can be found HERE
Locations of Long Shots and all collectibles with a timline are in the videos below.
Mission 1 - Siege of Tobruk
Mission 2 Gabroun
Mission 3 - Halfaya Pass
Mission 4 - Fort Rifugio
Mission 5 - Siwa Oasis
Mission 6 - Kasserine Pass
Mission 7 - Point Du Fahs Airfield
Mission 8 - Ratte Factory