Stress Relieving
A controlled heat process that removes machining and forging stress so a barrel does not shift its point of impact as it heats during a string.
Stress relieving is a controlled heat cycle that a barrel blank goes through to release the internal stresses left behind by drilling, rifling, and forging. Operations like button rifling and cold hammer forging work the steel hard and lock in tension, and if that tension is not relieved the barrel can warp unevenly when it gets hot. The result of skipping the step is a bore that “walks,” sending its point of impact drifting as the barrel heats up over a string of shots.
A properly stress-relieved barrel holds its point of impact far better as it warms, which is why reputable makers treat the step as mandatory rather than optional. It is a normal part of barrel manufacture and should not be confused with the colder, more debated cryogenic treatment, which some shops add afterward as a separate process.