The target in question was designed for the .44 bullet. The carton is therefore .44 of an inch diameter, the black bull’s-eye 1.32 in diameter leaving a ring of black round the carton of exactly a bullet width, i. e., .44.
The reason for having the black bull’s-eye three bullet diameters in width is because this leaves a space of exactly one bullet width between the edge of the white carton and the outer edge of the black bull’s-eye.
This gives a black ring, a bullet width, surrounding the bullet diameter carton.
Therefore when a bullet strikes the black of the bull’s-eye it can do one of three things.
It can cut partly into the white of the carton, it can cut partly into the white of the target outside the black bull’s-eye, or cut the black without touching the white on either side of it.
To decide if the carton is cut into (which would score one point higher than if the black of the bull’s-eye only was cut) examine first the edge of the bullet hole nearest the carton.
If this is uncertain, examine the opposite edge of the bullet hole, next to the white of the rest of the target.
If this is cut, then you know the carton cannot be cut, as the bullet hole is the exact width of the black.
To make assurance doubly sure, there is a thin line on the target, just clear of the outer black of the bull’s-eye.
If the bullet hole touches this thin line, then it is an absolute certainty that it cannot also cut into the carton.