According to an article I read on the Forbes Website (now those are words I  never thought I'd see myself typing), Call Of Duty: Black Ops 2 sold approximately 7.5 million units in the the United States in first week of release.  Now let's for a moment assume those figures are correct (although even if they are not they must have sold far in excess of those numbers but for now let's go with the figure of 7.5 million units).

According to a survey done in 2012 the population of the United States is  313 million people

According to one website there are between 76 and 120 million people in the United Sates that own a gun.

and just to reiterate, Black Ops sold 7.5 million units in the first week of release, which means for every person there is that bought Black Ops 2 in it's first week of release there are between 10 to 16 people that own a gun

That may not sound like much but when you compare it to the actual population of the United States for every one person that bought the game there are approximately 41 people that didn't

Black Ops 2 - Guns Ratio 1:10-16
Black Ops 2 - Population 1: 41
Gun Owners - Population 1: 2 - 4

My maths is probably incorrect as I'm doing this without double checking figures but it proves one thing and that is that there is more likely to be 10 times as many people that own a gun that bought black ops 2 in it's first week, that means that for every shooting, the odds are that person being both a black ops owner and a gun owner are slim and it is more likely they own a weapon not the game.

Hope someone will have the time to re-do this post to make it clearer and to double check the figures so they can be changed to be more accurate. 

This is the UK Edition:

http://ecx.images-amazon.com/images/I/916MbITzNPL._AA1500_.jpg