These are a set of three boresighting sticks (9mm, 308, 223) to reduce the effective diameter of your barrel at the muzzle. With the tube and your optionally installed aperture, you can increase the accuracy of your boresighting process.

Comes with custom box which uses M3 bolts and heat-set inserts. Contact for more information. You may need to tweak (either by hand or in CAD) the fit between the aperture pins and the boresight tube pins, as the slip fit is dependent on the accuracy of your printer.

Feel free to modify files as needed for your caliber/application, or contact me directly for assistance.

Credit to Hop for the idea