drjim want a Dillon Aero M134 Minigun.
It fires 7.62x51 NATO, and can be set to fire between 3000 and 4000 rounds a minute. A thousand rounds of 7.62x51 weighs about 52 pounds. Some quick counting on my toes (I am a Marine, after all) gets me to the idea that ten minutes of firing is a ton of ammo. Really, a ton, maybe a few pounds over.
So you really need a platform for it. A helicopter, a truck, a boat, something to carry the weapon on a base, provide electrical power, and carry the ammo.
7.62x51 is running about 50 cents a round, so that same 10 minutes of firing cost $20,000.00, more or less. I suppose you could get a discount for buying it by the semi-truck load.
Looks like a lot of fun, but I'm not sure one rich uncle would be enough. The major costs I can immediately see a big ranch in the Southwest for a range, helicopter(s), fuel, crews, Dillon minigun, spare parts, ammo, mechanics, armorers, and a company that was doing "development research" so that there would be justification for your possession of the system and those low level strafing runs on old cars. I'm thinking you might need Bill Gates as your uncle for this one.
Here it is, though, and drjim ever works all this out, I am ready to come out for a range day.