When dealing with a mystery barrel, an easy way to measure the twist rate of the rifling is a must.
Using a cleaning rod, a magic marker, and a tape measure, Chad with IV8888 goes through the basic steps to figure out the bore’s twist, which is needed to calculate ballistics and figure out a rifle’s sweet spot with certain loads.
Good stuff. Pretty soon you’ll be measuring everything in the safe, amazing your friends and baffling your enemies. Or something like that.