When measuring barrel lengths, go from the gas port on the operating side of the receiver to the muzzle. The gallery stamp s signify function and accuracy testing. The gallery stamp is to the right of these and may be either one or two symbols or letters. The magnaflux stamp is most often a symbol inside of a triangle and usually appears to the left of the proof mark, but also may appear to the right or below it. There are also symbols on the right side of the barrel. A hand stamp is used and can be difficult to read. Occasionally the charac t ers are weak or unevenly applied.
