Episode 186: Bouncing Bullet

Air Date: May 13, 2012

A driver being chased by another car can ricochet a bullet off the road surface and up through the pursuer’s floorboard to distract or injure him. (Inspired by a scene in the TV series Burn Notice.)

busted

Jamie fired into the undercarriage of a suspended car at point-blank range, using a 9 mm pistol similar to those used on the show. Balloons were placed inside the car to simulate enemies’ bodies; after several shots at a vulnerable area, he successfully broke one of them. He and Jamie then fired into pavement at various angles, measuring the speed and angle of the ricochets. A 16-degree angle gave the best overall performance, and the ricochet was able to penetrate a wheel well section set up as a target.

They then set up a trailer with a high-speed camera and measuring scale and towed it behind a pickup truck at 45 mph (72 km/h) as Jamie drove. When Adam fired the pistol, the speed and trajectory of the ricochet matched those from the stationary test. However, two 5-shot test runs with a target car in place of the trailer gave no penetration, due to bullets being deflected by other metal components in the underside. With the myth busted, Adam drove a car lined with bulletproof vests at 45 mph (72 km/h), triggering a pistol to shoot out one of his own tires. Although he did not immediately lose control, the tire had gone completely flat after 0.5 mi (805 m) and he was forced to stop. He and Jamie observed that shooting a pursuer’s tires was much more effective than trying to bounce a shot up through the floor.

The shock wave from an explosion can propel a jumping person to a distance far beyond what he could achieve on his own.

busted

Kari and Tory measured the distance and hang time of their own long jumps to serve as a benchmark for a typical person. While they achieved an average of 12 ft (3.7 m), their hang time was only 0.5 s, too short for an explosion to have any significant effect on their trajectory. Meanwhile, Grant built a nitrogen cannon to propel Buster and adjusted it to match the range and hang time of world-record jumpers (25 ft (7.6 m) and 1.0 s).

For full-scale testing, the Build Team set Buster up 50 ft (15 m) from an explosion site and fitted a trigger to set off the blast 0.5 s after he had jumped. A control run with no explosive gave a range of 27 ft (8 m); this result did not change when a 10 lb (4.5 kg) charge of C-4 was used. Switching to the lower-velocity explosive ANFO in 10, 25, and 100 lb (4.5, 11, and 45 kg) quantities did not improve his range. Finally, Tory built a steel frame and attached a blanket, sprayed with truck bedliner resin, to serve as a shock wave catcher and strapped Buster to it. Both a control run and a test with 100 lb (45 kg) ANFO gave a range of 23 ft (7.0 m), leading the team to judge the myth busted.

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