A medicament injection device including a needle, a first stage that controls positioning of the needle at a depth into an animal when the device is pressed against the animal, and a second stage that injects the medicament through the needle into the animal after the needle is positioned at the depth and the device is further pressed against the animal. The device preferably includes a mechanism that permits the second stage to inject the medicament only after the needle is positioned at the depth. The depth of the needle preferably is adjustable, as is the amount of the medicament injected. In preferred aspects, these two features are independently adjustable. One or more springs, pneumatics elements, or other elements may automatically reset the first stage, the second stage, or both after the device is withdrawn from the animal. Also, associated methods.