Projects in High-Speed Photography
Did you expect the strip as a whole to remain in place while the BB punched through the central portion? If you were surprised, consider this:
The area of the strip that first made contact with the BB was accelerated immediately. This area pulled on surrounding areas, exerting elastic forces to accelerate them. These areas, in turn, pulled on portions of the strip even further from the impact site. This chain of events did not travel instantaneously up and down the strip. The BB was moving quickly enough that it had time to penetrate the strip before the disturbance could reach the pushpin and pull the strip free.
Find out how a speeding BB can be stopped by a flimsy piece of elastic.
Find out how the photos were taken.