I know people who have private "collections" of over 500 and have plenty of ammo for all the ones that still operate(some are very old)...
I know people with automatic weapons collections(all legal)...
Check out my friend John Ross who wrote Unintended Consequences...
His website is
www.john-ross.net and he's also got a video or two on the internet of him shooting some of the auto stuff...
Those Glock G18 auto pistols are wicked!
And his book is available through Accurate Press(
www.accuratepress.net).