Technical Information: Material: Steel Precision Machining -This is a one-piece and non-adjustable cylinder-type gage for checking fired and resized cartridge cases for cone-to-head and overall length -Used to compare cartridges against the minimum SAAMI chamber dimensions Instructions: -Drop a fired case into the gage. Take a measurement on headspace. This can be done with either a depth micrometer or caliper (Depending on if the case is sitting high or low in the gage). If the case sticks out past maximum headspace the firearm probably has a larger than average chamber. The gage can still be used because it is being used to determine how much resizing is required. -Now once the initial measurement is taken and slowly dial in the full length sizer until there is a 0.001 to 0.002 drop in headspace. This will give the measurement to resize the case just below the chambers headspace in the firearm being reloaded for and giving a more accurate shot and saving brass by not causing it to be overworked. -Once the brass has been sized and set the brass in the gage and set the gage on a flat surface with the head side facing down. Now look across the top of the gage and this give the maximum and minimum for trim length.
