Final answer:
The primer cap in the center of the casing is more likely to have breech face markings due to the dynamics of the firing process.
Step-by-step explanation:
Breech face markings on the primer cap of a casing are more likely to be found in the center rather than outside because of the dynamics of the firing process. The primer cap is located in the center, and when the firing pin strikes it, it creates a dent or impression on the breech face. This dent is transferred to the primer cap, leaving a marking.
Outside the primer cap area, there is less contact between the breech face and the casing. Therefore, the chances of finding breech face markings decrease as you move away from the center.
For example, in a semiautomatic pistol, the firing pin strikes the primer cap in the center of the casing. This creates a characteristic impression which can be used for forensic analysis, such as identifying the weapon used in a crime.