This "Barrelstick" is the Official barrel length measuring tool for the Gallactic Pistol Alliance competition series.
It is a specialized Squib rod designed to also measure your barrel length quickly and easily to verify compliance.
Ensure your gun is clear and unloaded then simply insert the Barrelstick into the end of your barrel until it stops on the breech face and then see where the end of the barrel aligns with the grooves in the Barrelstick.
The first groove is for 4.1" long barrel checks and the second groove is for 5.4" barrels.
The groove width is the allowable tolerance (0.09") for each barrel length. If the groove is still visible and not below the inner edge of the barrel then your gun is legal for that barrel length.
From our testing we have found that a lot of barrels ARE NOT the same length as the manufacturer markets them so it's always worth checking!