SDI Advanced Ballistics (BBS 200) Practice Exam

The tool that measures the radial run out of a finished round is the concentricity gauge. This device is specifically designed to assess how much the axis of the bullet deviates from the centerline of the cartridge case or the overall length of the round.

Radial run out refers to the degree to which a round is not perfectly centered, which can affect accuracy and consistency. The concentricity gauge can precisely determine this deviation, allowing for adjustments in the manufacturing process to ensure that rounds perform reliably and accurately.

Other tools such as calipers, micrometers, and dial indicators are valuable in various measurement contexts but are not specifically tailored for evaluating the concentricity or run out of ammunition. A caliper measures outside and inside dimensions, a micrometer measures small distances with high precision, and a dial indicator is typically used for measuring linear displacements. While they can provide useful measurements, they do not focus exclusively on the concentricity needed for ensuring the radial run out of a round.