I discovered a crooked chambering when I scoped a new rifle. Fortunately, I ran the bore scope through the barrel before shooting it. The manufacturer argued with me that the rifle was fine, until I threatened to name the maker and post the photos. They installed a new barrel and had it back to me within 3 weeks. This has happened to me twice, different brand each time. The Teslong bore scoped paid for itself in just that one use. Now, I bring the Teslong with me whenever buying a rifle, new or used. Interestingly, I see these crooked chambers more often in new guns than old guns. I wonder how many people are out there hopelessly flogging away trying countless different handloads on a rifle with a crooked chamber.