20 acres in downtown Vegas? Not a chance. That was barely bigger than an acre which helped him because the targets were packed together. I had the same question about the physical ability to do this and it seems from responses here that he could have. Then the real question is who supplied him and the guns and why did he do it. There can’t be that much mystery here. I think we’re just not being told because the media doesn’t want to.
“Then the real question is who supplied him and the guns”
Huh? “Supplied?” He bought them. Anyone can go buy an AR and put a bump stock on it.
You can find everything he used on the major firearms sites online. Installing the optics is easy, as is installing a bumpfire stock. I heard one of them last week at my local range (I didn't go look because wasting ammo annoys me, and shooting just to hear "bang" strikes me as a waste). As for why he did it, I imagine we will find out soon.