There are somewhere around 200-, 250-, and 300-million guns in the US, depending on who/what you read.
Here's a pic graph of the distribution of guns in the US, by State.
But sometimes it's hard to get a visual image of large numbers, like how many is 250 million ?
It turns out there are about 250,000,000 automobiles currently registered in the US.
So for every car you see, there's a gun out there.