There are more than 52 million gun owners in the United States. The data you published is for number of "homes" that have firearms in them, and that estimate suggests 52 million homes contain atleast ONE firearm.
From the article you cited: "Remove those that skew the stats for their own purposes the best estimates are about 45% or 52 million of American HOUSEHOLDS owning 260 million guns."
These numbers still are not correct, because this only involves those that willingly give the information to those conducting polls. I would be nervous informing someone who called my home that I own firearms, regardless of who they say they are calling for or why. So I would guess even the number of homes that have a firearm in them are much higher than the polls suggest. Even the number of firearms they suggest are in civillian hands is incorrect. Twenty years ago the BATF suggested there were close to 230 million firearms in civillian possession, and there has been well over one-hundred million firearms sold since then.
In late '94 55% of those polled said they had firearms in their home, but just a year later only 40% said they had a firearm in their home? We had a RECORD year this year concerning number of firearms sold, with the most ever sold in one year! When the political environment heats up and people begin thinking strict laws are heading our way they are hesitant to admit to gun ownership.
In the first three months of 2012, there were 5.6 million NICS checks conducted for gun sales. This is an adjusted number that removes those conducted for other activities. When you figure that more than one firearm can be purchased per check, then this gives us a broad idea of how many firearms were sold in just THREE months! By the end of November, 2012, there were over 16 million NCIS checks conducted for firearm purchases, and I would bet December will have several million as well (I would bet over 5 million easy).