British and European firearms have been subjected to something called proof testing to ensure they won't blow up on the user. From the Firearms History, Technology and Development blog:
Proof tests were instrumental in protecting the end-user from weapon failures and compulsory enforcement of these laws helped reduce firearm-related accidents around the world. This is why they are still mandatory in many countries. I remember discussing this matter with my Torts teacher in law school and he mentioned something about product liability, which has been something I filed away in my brain. I associated these tests primarily with British firearms, but they seem to be much more common. The point is that firearms have an inherent lethality which adds to their attractiveness. They cause serious injury or death when used properly.The first type of testing we will study is the Proof Test. The idea behind such a test is to verify the strength of the barrel, breech and firing system of a firearm by deliberately firing an over-pressured cartridge. After this, the firearm is examined to make sure it is still intact and if so, the metal (usually the barrel) is stamped with one or more "proof marks" of the testing agency. The proof marks create indented impressions on the metal surface, so they cannot be accidentally removed. Such a test certifies that the firearm is free from manufacturing defects and will not explode under normal usage conditions. In many countries, proof tests are compulsory; and it is not possible to sell a firearm unless it has been proof-tested by an official testing agency approved by the government.
Some manufacturers in the town of St. Etienne in France started conducting proof tests around the 15th century, when firearms manufacturing started in that area. However, France didn't enact a law to make the test mandatory until the 1900s and hence, it was left to each French manufacturer to decide what the test standards should be or even whether to perform a test or not. In other areas, such as London and Birmingham in England and Liege in Belgium, even before testing became compulsory, most manufacturers used to do private tests in their own factories or in a trade testing house.
Compulsory testing laws were passed in most countries mainly due to the backing of the gunmaker guilds of those countries. By enacting such laws, the guilds sought to prevent the manufacture of firearms and stifle competition from non-guild members, even though they claimed that such laws were designed to protect members of the public. The first such compulsory law was passed due to the lobbying efforts of the London Gunmakers Company (a guild composed of firearm manufacturers around London). The initial bylaws passed by the London Gunmakers Company charter of 1637 marked the first introduction of proof tests in England, but didn't specify an official standard of testing.
https://firearmshistory.blogspot.com/2011/01/testing-firearms-proof-test.html
On the other hand, it is their lethality and dangerous nature which leads to their being regulated in pretty much all civilised nations. And having been regulated for a very long time.
