Concentricity, Wall Thickness and Runout GaugeThe NECO, patented, Case Gauge is the most versatile instrument available for measuring the various accuracy determining factors of cartridge cases, bullets and loaded ammunition. No other gauge can measure all of the following: 1.Banana curvature of case. 2.Wall and neck thickness variations. 3.Case head squareness. 4.Banana curvature and out-of-round shape of individual bullets. 5.Runout of seated bullet. 6.Total runout of loaded cartridge. The "Case Gauge" can be used to measure cartridges from .17 cal to .50BMG by purchasing the appropriate "chord anvil".