Measurement Tool

 Careful measurements are often crucial in gunsmithing work. They may reveal a dangerous level of wear, or an out-of-spec part. The most frequently used measuring tool in gunsmithing is probably the dial caliper, which usually reads from zero to six inches in .001-inch graduations. Followed by Micrometers for ultra-precise measurements of a barrel diameter, metal thickness, bullet diameter, etc., you should have a six-inch steel rule graduated in 32nds or even 64ths.