Full-auto weapons are extremely scarce on the civilian market, making them very expensive. The paperwork supposedly isn't all that bad (I haven't done this myself). $200 tax on any NFA weapons including machine guns, silencers, and "destructive devices". You just need to fill out some forms for the ATF and then get a local law enforcement official (only certain positions count, you'd have to check the forms) to authorize it. There's also an FBI background check. You can get around the sign-off and background check by setting up a corporation or trust or other legal entity that is the purchaser of the guns. Once the ATF says you're clear all you have to do is take the paperwork to your Class III firearms dealer and pick out what you want. EDIT: check out http://www.autoweapons.com/products/products.html some of them have prices listed.
A pump action shotgun is the ticket for home defense, IMO. Nothing will make a bad guy soil his ripped jeans like the sound of a round being chambered in a pump. Everybody knows what that sound is, and what it means. Some may argue that it takes longer to rechamber a new round than a semi-auto, and that is correct. But one is generally seeking new targets during that period anyway, so it's not a real drawback. Complete morons suggest that the pellet spread is so high that shotguns are useless beyond 10 feet or somesuch. Now, you don't want to shoot a deer half a mile away with one, but the pellet grouping is very tight in any in-home encounter. Which means one needs to practice to be capable, even with a shotgun.
To obtain automatic weapons you must have a federal firearms license. Practically impossible to get. Plus you have to live in a state that allows them. Only a few do.
You don't need the FFL to purchase/posess automatic weapons, you only need it if you are a dealer (who needs a class III to deal in auto. weapons). It is true that what you are allowed to own varies by state and sometimes city.
How effective is a shotgun against someone wearing a vest or body armor? Pretty effective I'm guessing if you manage a head shot or maybe a leg shot, and I suppose a full load of 00 would at least knock them off their feet. I think the issue of an intruder wearing at least a vest is something you have to take into account for a home defense weapon. I don't believe a standard vest will stop a 5.56 round. That's one reason the Kel-Tec seems to have potential to me.
In your opinion??? Khahahahahahaha Who cares about your opinion Tigger!!! You know what I used to do to people like you? I used to beat them to the point of begging for mercy just to expose them to the rest of the people who they love to intimidate. Luckily for you, you could brag about shot guns on cyber space bitch.... Let me ask you a question and be honest with me...Girls always told you "Is that it?" didn't they. "In your opinion"??? Khahahahaha...Such a funny guy you are Tigger!