Ever wonder why England established a proof house? Well, a zillion gunsmiths were turning out a zillion guns, many for export to Africa and other parts far away from England and many for domestic use. And many guns blew up in a shooter’s face with the first pull. Didn’t help the English reputation when they tried to trade guns for slaves and ivory, or for the local laborers, etcetera. And these makers were basically immune from liability which was more or,less an unknown concept. Who cared! So in an effort to save a valuable export item from extinction the government established a proof house in London in 1657, requiring all guns to undergo proofing. Guns still blew up after sale but maybe the proud owner could get a dozen or so shots before each pull became a game off roulette. And to varying degrees this problem continued for a couple centuries. So the proof houses became integral to the British arms trade and did raise the overall safety significantly. *
Fast forward to the American manufacture of arms. They were late comers to the business and while the individual makers turning out one longrifle at a time did the best they could since their market was local—close neighbors—and reputation was the only thing that kept them in business. But admittedly they often produced very inferior arms to the Indian trade. But by the time true arms factories (Colt first) began producing arms, liability laws were pretty well established. And also each arms manufacturer depended on a good reputation. As a result each manufacturer became their own proof house and subjected their guns to rigorous stress tests. So the same self regulation has successfully continued to this day, perhaps even more strenuous today than ever before since it’s increasingly easy to sue for inferior products.
*Much of this from writings of WW Greener.