Measuring grid of the eyepiece
Courtesy of Ronnie Freels
The process for measuring land and groove impressions with a glass reticule is as follows:
- Place the bullet on a fixed mount that can be rotated.
- Rotate the bullet to the selected land or groove impression.
- Bring both reference points into focus.
- Superimpose the measuring grid of the eyepiece on the surface of the bullet.
- Take a measurement reading to the nearest thousandth of an inch.
- Rotate the bullet to the next land or groove impression and repeat steps 3 – 5.
It is important to note that both of the eyepieces of the microscope must be adjustable to use this technique.
The steps for measuring land and groove impressions using electronic reticules are the same as those for glass reticules.