I have seen exactly one gun let go with factory loads. It was a K-80. The owner never reloaded and was extremely good about keeping his almost new gun in factory original shape. Much debate and hand wringing at the time never concluded the real cause. But he did get a new barrel and for end stock put on the gun by the maker. Not that they assumed any fault. Just to make him happy.
Most gun failures, when it is not the guns fault for being rusted out or pitted to a weak point, are the reloaders fault. If your gun is weak any shell could cause a failure. Most guns are in solid shape and take that extra measure of pressure or extra measure of dumb to make them fail. Get a base wad stuck in the barrel and they might fail. Use the wrong powder and they might fail. Use the wrong bushing and they might fail. Almost all gun failures are induced by the shooter by his error in my opinion.
