What determines if an enemy is killed or downed in Gears of War 3?

I've noticed sometimes when I purposely shoot an enemy in the leg in bursts I kill them. Other times, I down them.

I thought the main reason to shoot an enemy in the leg is to slow them down and to down them so an execution can be performed. I've noticed this is not the case and appears to be random.

Does the game randomly decide whether or not to down an enemy no matter where you shoot? Apart from when the enemy is shot in the head.

Solution 1:

An enemy should only ever get downed from normal fire from guns like the lancer etc. Killing someone immediately by shooting them in the legs with a lancer should never happen.

An enemy will be killed if:

• Hit by a head shot from a; Longshot, Boltock Pistol, Gnasher shotgun.

• Directly hit by a; torque bow, boom shot, frag grenade, incendiary grenade, one shot, sawn off shotgun, mortar, charged bayonet from the retro lancer, chainsaw from the lancer, digger.

• An enemy has already been downed twice, the third time they are dead.

• You are shot when you are down.