Part of it is the holes are fairly uniform, but the big tell is no “flaps” poking outward. A drill removes material as it drills, so only a little is left over to flap out when the drill pokes through. A bullet would have to push ALL of the material from the hole outward, which would be a lot of material for a one inch thick hole.
From the photo it looks to me like there is some material being pushed out the front from the back, so unless you know of a way that a high speed bullet moving toward a metal sheet would pull material backward as it moves forward then it would be hard for it be shot from the front.
What is clean about them?
Part of it is the holes are fairly uniform, but the big tell is no “flaps” poking outward. A drill removes material as it drills, so only a little is left over to flap out when the drill pokes through. A bullet would have to push ALL of the material from the hole outward, which would be a lot of material for a one inch thick hole.
So you assume it was shot from the back? Why not front?
From the photo it looks to me like there is some material being pushed out the front from the back, so unless you know of a way that a high speed bullet moving toward a metal sheet would pull material backward as it moves forward then it would be hard for it be shot from the front.
Why should a drill push that much out?