Use the following trick to have essentially unlimited ammunition for knocking out enemies. This does not work until after you have found the SC-20K and have Sticky Cameras. If you are close to an enemy and want to knock him out, shoot him in the head with a Sticky Camera. It will knock out your enemy, and you can then pick the camera up off of the ground.

For a convenient attack on a guard or character without being noticed, fire a Sticky Camera (not a Diversion Camera) at your targets' head. Due to gravity, aim slightly higher, near the top of the head or above it. This saves bullets, eliminates the risk of being seen, and you can pick up the cameras and use them again.