I have heard various answers from people in law enforcement but are there certification courses that a civilian can take that will allow them to legally own, operate, and/or carry firearms that fall under FFL levels 2&3 or is just having the tax stamp enough? For instance, I have a very small apartment and I would like to buy a short shotgun so that I can move freely around my home and be able to quickly present the shotgun if there is an intruder, however there are laws prohibiting me, as a civilian from owning a shotgun with a barrel that is less than 18" or one that is under a certain over-all length. Is there a class I could take that would allow me to own and use a firearm like this legally? I would also like to purchase a suppressor for my .45 because I am concerned that if I had to discharge my firearm in an emergency, self defense situation, in my home, that I could damage my hearing.

I have talked with retired police officers, military personnel, and gun store employees and received very mixed answers on this subject. I realize it probably depends a lot on where I live. I live in Virginia, a shall issue state so I would think, with the exception of maybe Florida or some Western states that are even more relaxed on gun control, if it is possible to obtain a license or certification to own something like this I would be able to here. I have, as I stated before, also heard that simply paying the tax stamp and going through a 2 or 3FFL dealer would be enough but I would like to make sure so I don’t create any trouble for myself. Thanks for any help.
I was asking more in generality tho. Most of the FFL 2&3 firearms I am interested in I wold like to have simply to take out to the range and have a good time with. The short shotgun and suppressor are two of the few I would pick as ideal self defense.

Unknown, I own both a .45 1911 and a 9mm Baby Desert Eagle, I practice often at the range but I have been present for an accidental discharge in tight quarters and it is very loud. Also, I live in a rough area and have had armed men at my doorstep on more than one occasion, fortunately the sound of racking the slide on my .45 has been enough of a deterrent to avoid an incident. I have confidence in my shot placement when I am awake but the shotgun takes less thinking if I were to wake up out of a dead sleep and need to defend myself, my loved ones and/or my home.

Eddie, I realize the laws about the length, but as I said I am in extremely cramped quarters so it would be advantageous for me to have a smaller framed firearm.
Also Unknown you said "not in Virginia". Did you mean that there are states that Do issue a permit or license for these kind of firearms? I was watching some behind the scenes features on a DVD and they said that the weapons master on the set is one of the only civilians in the country licensed to own, operate, and supervise the use of a Glock 18c, which is a fully automatic handgun. That statement is actually one of the major things that sparked my interest and led me to ask this question.