I'd like to share some insight with you all from the point of view of someone in the business. I recently retired after a 20 year career in the firearms industry spent in the areas of firearms design, manufacturing, and retail.
The idea of making manufacturers "responsible" for the neglegent and criminal use of their product is quite problematic. The big problem is the fact that I have no control over what a person does with their firearm once it leaves the retail store. I cannot stop any individual from making the personal choice to use my guns in an illegal or neglegent manner any more than auto manufacturers can control how people drink and drive.
With regards to having a person with a clean record purchase a firearm for a convicted felon, that is indeed known as a "Straw Purchase" as another person here mentioned. A Straw Purchase is a violation of federal law, and is a felony punishable by 10 yrs in prison as well as a $10,000 fine. The BATFE works very closely with FFL holders on different methods to spot and prevent such purchases. And there are alot of people who do get caught and convicted. It's not a difficult thing for a sales person at a retail shop to spot a straw purchase. Also, those employees jobs depend on the FFL holder/owner keeping their license. They are protecting their own job by scrutinizing a potential customer. Many, many people are asked to leave gunshops and to never return for attempting an illegal purchase.
The BATF (now called the BATFE) drastically cut down on FFL holders who were hobby/garage dealers. There are about 420,000 FFL holders in the US right now. Before the crackdown on shady/grey area dealers there were over 1,000,000 FFL's being held. All the retail dealers I know, and I know alot of them, follow the federal regs TO THE TEE. They keep excellent records, and do not consider the BATFE an adversary, but rather an agency who assists them in keeping the firearms they sell from being purchased by prohibited persons.
Also, people in the firearms industry are a tight knit group, and as such, we police our own. A single shoddy dealer can reflect very badly on an industry that is already demonized in the news media. In regards to which type of firearms should be allowed, and which one's should not, well that's a completely irrelevant matter as firearms, are firearms.
One person here asked if they could own an UZI Submachinegun. If you reside in one of the 38 states that allow ownership of Class III weapons, you can can buy a fully automatic weapon. But first you must fill out a lengthy application, get a fingerprint card done, have the Chief Law Enforcement Officer in your area sign off on the form attesting to your character and status as a law abiding citizen. You then send the paperwork, and pay a $200 transfer tax on the weapon. After six to nine months the BATFE will complete a thorough background check and if approved, send you your transfer tax form. Only then can you take posession of the weapon you purchased.
I've heard many people say that you can just walk into a gunshop in the US and walk out with a machinegun. That is 100% incorrect and untrue.The dealer keeps it until all is done and approved. And, since there are only a fixed number of legal, registered, and transferable automatic weapons in the national pool, you will pay a small fortune for your automatic weapon. The Average prices for an IMI Uzi in 9mm is between 18 and 20 thousand dollars. A weapon like a B.A.R., or Thompson SMG can fetch anywhere from 20 thousand to over 100 thousand dollars. No legally owned automatic weapon has ever been used in a crime since the Gun Control Act of 1932 and 1936 went into effect.
As for the ownership of items such as an RPG, LAW rocket, small artillery and such, there is no legal way for a citizen to acquire these items known as "Destructive Devices". So the questions about owning rockets and howitzers is completely irrelevant-you cannot have one.
Finally in regards to people buying multiple guns, purchasing more than 2 firearms in a 7 day period will cause the dealer to submit a multiple sale report directly to the BATFE via fax, and the original sale report via mail. This law was recently expanded to include all firearms, not just handguns. The purpose of the report is to stop firearms being purchased in bulk from a dealer and then sold via black market to prohibited individuals.
Anyway, I hope I've answered some questions and cleared up some confusion on the subject.