You can have most of those things if you register them (and pay a hefty fee). The ammunition would have to be registered individually and separately, so a legal arsenal is very expensive.
How many people have been killed by privately owned anti-tank weaponry, for example? Gangsters are not interested in them because 1) it's silly expensive and 2) every cop and g-man in America will want to bag the the guy who uses it in a mod hit.
Seriously, most of the gun murders in America are from pistols, which is the opposite of your argument.
Ronin - why don't you ask someone in a place with high gun ownership? I suspect that you don't have much experience with such a place. I know I don't.
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